Electric working vehicle, electric garden working vehicle and electric riding type mower

Abstract

The embodiment of the invention provides an electric working vehicle, an electric garden working vehicle and an electric riding type mower, which can timely and accurately identify heavy load sudden change conditions and take corresponding control measures, improve the stability of the whole machine and optimize the application experience of a user. The electric working vehicle comprises a functional motor and a controller, wherein the functional motor has various operating parameters and various control strategies correspondingly matched with the various operating parameters; the heavy load identification unit is configured to select a target operation parameter which is not matched with a currently adopted first control strategy from the multiple operation parameters for monitoring, and determine whether the functional motor enters a heavy load state or not according to the target operation parameter and / or the change condition of the target operation parameter; and in response to determining that the functional motor enters the heavy-load state, the heavy-load control unit controls and adjusts the functional motor so as to enable the functional motor to exit the heavy-load state.

Description

Electric work vehicle, electric garden work vehicle and electric riding lawn mower [Technical field]

[0001] The present invention relates to the technical field of vehicle engineering, and in particular to an electric working vehicle, an electric gardening vehicle and an electric riding lawn mower. [Background Technology]

[0002] Compared to traditional fuel-powered mowers, cordless mowers offer all-weather zero emissions, zero fuel consumption, low noise, and simplified maintenance (no gasoline, oil, air filter, spark plugs, or fuel storage). They utilize an electric motor, rather than a fuel engine, as the power source, powering both the drive wheel motor and the mowing motor. Cordless mowers can independently control each drive wheel motor, enabling movement control for straight driving, reverse driving, cornering, and zero-turn maneuvers. This reduces the vehicle's structural complexity and provides greater control flexibility.

[0003] During operation, the actual grass density will affect the working load of the lawn mower. When the grass density changes from low to high, the load on the mower motor will often suddenly increase. The output power and operating current of the mower motor will also increase instantly, which may cause overcurrent damage to the motor or trigger the overcurrent protection and shut down the mower. This situation will seriously affect the stability of the whole machine and the user experience.

[0004] [Summary of the invention]

[0005] In view of this, the embodiments of this specification provide an electric work vehicle, an electric garden work vehicle, and an electric riding lawn mower that can promptly and accurately identify sudden changes in heavy loads and take corresponding control measures to improve the stability of the entire machine and optimize the user experience.

[0006] In one aspect, embodiments of the present disclosure provide an electric work vehicle, comprising:

[0007] Motor;

[0008] an acquisition module, the acquisition module being configured to acquire at least one mechanical parameter and at least one electrical parameter of the motor, the mechanical parameter including a speed parameter, a sector time parameter, or a torque parameter, and the electrical parameter including a bus current parameter, a phase current parameter, a bus voltage parameter, a power parameter, a freewheeling time parameter, or a duty cycle parameter;

[0009] a detection module, configured to process the mechanical parameters and electrical parameters of the motor according to a target calculation formula and generate a target value, wherein the target calculation formula includes at least a ratio, a slope of the ratio, or a difference of the ratio;

[0010] A judgment module is used to determine whether the motor is in an overload state based on the target value and the target preset threshold value. If the target value does not meet the target preset threshold value, it is determined that the motor is in an overload state, wherein the target preset threshold value corresponds to the target calculation formula.

[0011] Optionally, the speed parameters include: speed, speed difference or the slope of the speed curve, the sector time parameters include: sector time, sector time difference or the slope of the sector time curve, the torque parameters include: torque, torque difference or the slope of the torque curve, the bus current parameters include: bus current, bus current difference or the slope of the bus current curve, the phase current parameters include: phase current, phase current difference or the slope of the phase current curve, the bus voltage parameters include: bus voltage, bus voltage difference or the slope of the bus voltage curve, the power parameters include: power, power difference or the slope of the power curve, the freewheeling time parameters include: freewheeling time, freewheeling time difference or the slope of the freewheeling time curve, the duty cycle parameters include: duty cycle parameters, duty cycle parameter difference or the slope of the duty cycle parameter curve, and the target value is the ratio of the same type of the mechanical parameter to the electrical parameter.

[0012] Optionally, the target calculation formula includes: calculating the ratio of the mechanical parameters to the electrical parameters of the motor, or the ratio of different electrical parameters of the motor, and the target value is the ratio. The judgment module also includes: comparing the ratio with the target preset threshold, and if the ratio does not meet the target preset threshold, determining that the motor is in an overloaded state.

[0013] Optionally, the target calculation formula includes: calculating the ratio of the mechanical parameters to the electrical parameters of the motor, or the ratio of different electrical parameters of the motor, and calculating the ratio of the ratio to the preset ratio, the target value is the ratio value, and the judgment module also includes: comparing the ratio value with the target preset threshold value, if the ratio value does not meet the target preset threshold value, determining that the motor is in the overload state.

[0014] Optionally, the target calculation formula includes: calculating the ratio of the mechanical parameters to the electrical parameters of the motor, or the ratio of different electrical parameters of the motor, and calculating the difference between the ratios within a preset time, and the target value is the difference. The judgment module also includes: comparing the difference with the target preset threshold, and if the difference does not meet the target preset threshold, determining that the motor is in the overload state.

[0015] Optionally, the target calculation formula includes: calculating the ratio of the mechanical parameters to the electrical parameters of the motor, or the ratio of different electrical parameters of the motor, and obtaining the slope of the curve of the ratio, the target value is the slope, and the judgment module also includes: comparing the slope with the target preset threshold, if the slope does not meet the target preset threshold, determining that the motor is in the overload state.

[0016] Optionally, the motor includes: a first gear, a second gear and a third gear with increasing output capacities in sequence, and the target preset threshold is the same when the motor is in the first gear, the motor is in the second gear and the motor is in the third gear; or, the target preset threshold decreases in sequence when the motor is in the first gear, the motor is in the second gear and the motor is in the third gear; or, the target preset threshold increases in sequence when the motor is in the first gear, the motor is in the second gear and the motor is in the third gear.

[0017] Optionally, the target preset threshold is determined according to the sampling time, and the shorter the sampling time interval, the smaller the target preset threshold. The sampling time interval is: the time interval for obtaining two adjacent mechanical parameters or obtaining two adjacent electrical parameters.

[0018] Optionally, the electric work vehicle further includes: a control module, which is used to adjust the mechanical parameters or electrical parameters of the motor when the motor is in the overload state to reduce the working efficiency of the motor until the motor is out of the overload state.

[0019] On the other hand, an embodiment of this specification provides a method for detecting a heavy load state, which is applied to an electric work vehicle, comprising:

[0020] Collecting at least one mechanical parameter and at least one electrical parameter of the motor, the mechanical parameter including a speed parameter, a sector time parameter, or a torque parameter, and the electrical parameter including a bus current parameter, a phase current parameter, a bus voltage parameter, a power parameter, a freewheeling time parameter, or a duty cycle parameter;

[0021] Processing the mechanical parameters and electrical parameters of the motor according to a target calculation formula to generate a target value, wherein the target calculation formula includes at least a ratio, a slope of the ratio, or a difference of the ratio;

[0022] Determine whether the motor is in an overload state based on the target value and the target preset threshold value. If the target value does not meet the target preset threshold value, determine that the motor is in an overload state, wherein the target preset threshold value corresponds to the target calculation formula.

[0023] In another aspect, an embodiment of the present specification further provides an electric work vehicle, comprising:

[0024] Frame;

[0025] a functional mechanism attached to the vehicle frame, comprising a functional motor and an output assembly driven by the functional motor to perform a specific functional operation;

[0026] A controller component, used to control the operating state of the functional motor;

[0027] The functional motor has a plurality of operating parameters, and the controller component has a plurality of control strategies corresponding to the plurality of operating parameters for the functional motor;

[0028] The controller assembly includes a heavy load identification unit and a heavy load control unit;

[0029] The overload identification unit is configured to select a target operating parameter from the plurality of operating parameters for monitoring, and determine whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter;

[0030] wherein the target operating parameter does not match a first control strategy currently adopted by the controller component for the functional motor;

[0031] In response to determining that the functional motor enters the overload state, the overload control unit is configured to select a second control strategy from the multiple control strategies, and control and adjust the functional motor based on the second control strategy to make it exit the overload state.

[0032] Optionally, the multiple operating parameters of the functional motor include speed parameters, electrical parameters, power parameters, torque parameters and PWM duty cycle parameters;

[0033] The various control strategies corresponding to the various operating parameters are speed closed-loop control strategy, current closed-loop control strategy, power closed-loop control strategy, torque closed-loop control strategy and PWM duty cycle open-loop control strategy.

[0034] Optionally, the overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including:

[0035] In response to the rotational speed parameter not matching the first control strategy, the heavy load identification unit is configured to select the rotational speed parameter as the target operating parameter;

[0036] The overload identification unit is further configured to monitor the speed parameter and determine whether the functional motor enters an overload state according to the speed parameter and / or a change in the speed parameter.

[0037] Optionally, the speed parameter includes a motor speed parameter;

[0038] The overload identification unit monitors the speed parameter and determines whether the functional motor enters an overload state according to the speed parameter and / or a change in the speed parameter, including:

[0039] During operation of the functional motor, determining whether the motor speed parameter is greater than or equal to a corresponding preset motor speed parameter threshold;

[0040] In response to the motor speed parameter being greater than or equal to the corresponding preset motor speed parameter threshold, it is determined that the functional motor enters a heavy load state.

[0041] Optionally, the motor speed parameters include motor speed, motor speed difference and motor speed change rate;

[0042] The motor speed difference refers to the difference between the motor speeds of the functional motor at two adjacent moments;

[0043] The motor speed change rate is used to represent the change trend of the motor speed of the functional motor at a corresponding moment;

[0044] The overload identification unit determines whether the motor speed parameter is greater than or equal to a corresponding preset motor speed parameter threshold during the operation of the functional motor, including:

[0045] At least one motor speed parameter is obtained, and it is determined whether the at least one motor speed parameter is less than or equal to a corresponding preset motor speed parameter threshold.

[0046] Optionally, the speed parameter includes a motor sector time parameter;

[0047] The overload identification unit monitors the speed parameter and determines whether the functional motor enters an overload state according to the speed parameter and / or a change in the speed parameter, including:

[0048] During operation of the functional motor, determining whether the motor sector time parameter is greater than or equal to a corresponding preset motor sector time parameter threshold;

[0049] In response to the motor sector time parameter being greater than or equal to the corresponding preset motor sector time parameter threshold, it is determined that the functional motor enters a heavy load state.

[0050] Optionally, the motor sector time parameters include motor sector time, motor sector time difference and motor sector time change rate;

[0051] The electrical cycle of the functional motor includes a plurality of sectors, and the motor sector time refers to the corresponding duration of each sector;

[0052] The motor sector time difference refers to the difference between two adjacent moments corresponding to the motor sector time;

[0053] The motor sector time change rate is used to characterize the change trend of the motor sector time;

[0054] The overload identification unit determines whether the motor sector time parameter is greater than or equal to a corresponding preset motor sector time parameter threshold during the operation of the functional motor, including:

[0055] At least one motor sector time parameter is obtained, and it is determined whether the at least one motor sector time parameter is greater than or equal to a corresponding preset motor sector time parameter threshold.

[0056] Optionally, the overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including:

[0057] In response to the electrical parameter not matching the first control strategy, the overload identification unit is configured to select the electrical parameter as the target operating parameter;

[0058] The overload identification unit is further configured to monitor the electrical parameters and determine whether the functional motor enters an overload state based on the electrical parameters and / or changes in the electrical parameters.

[0059] Optionally, the overload identification unit monitors the electrical parameters and determines whether the functional motor enters an overload state according to the electrical parameters and / or changes in the electrical parameters, including:

[0060] During operation of the functional motor, determining whether the electrical parameter is greater than or equal to a corresponding preset electrical parameter threshold;

[0061] In response to the electrical parameter being greater than or equal to the corresponding preset electrical parameter threshold, it is determined that the functional motor enters a heavy load state.

[0062] Optionally, the electrical parameters include bus current parameters;

[0063] The bus current parameters include bus current, bus current difference and bus current change rate;

[0064] The bus current difference refers to the difference between the bus currents of the functional motor at two adjacent moments;

[0065] The bus current change rate is used to characterize the change trend of the bus current of the functional motor at a corresponding moment;

[0066] The overload identification unit determines whether the electrical parameter is greater than or equal to a corresponding preset electrical parameter threshold during the operation of the functional motor, including:

[0067] At least one bus current parameter is obtained, and it is determined whether the at least one bus current parameter is greater than or equal to the corresponding preset electrical parameter threshold.

[0068] Optionally, the electrical parameters include phase current parameters;

[0069] The phase current parameters include phase current, phase current difference and phase current change rate;

[0070] The phase current difference refers to the difference between the phase currents of the functional motor at two adjacent moments;

[0071] The phase current change rate is used to characterize the change trend of the phase current of the functional motor at a corresponding moment;

[0072] The overload identification unit determines whether the electrical parameter is greater than or equal to a corresponding preset electrical parameter threshold during the operation of the functional motor, including:

[0073] At least one phase current parameter is obtained, and it is determined whether the at least one phase current parameter is greater than or equal to the corresponding preset electrical parameter threshold.

[0074] Optionally, the electrical parameters include bus voltage parameters;

[0075] The bus voltage parameters include bus voltage drop, bus voltage drop difference and bus voltage drop change rate;

[0076] The bus voltage drop refers to the drop in the bus voltage during the operation of the functional motor compared to the bus voltage before the motor starts working;

[0077] The bus voltage drop difference refers to the difference in bus voltage drop of the functional motor at two adjacent moments;

[0078] The bus voltage drop change rate is used to characterize the change trend of the bus voltage drop of the functional motor at a corresponding moment;

[0079] The overload identification unit determines whether the electrical parameter is greater than or equal to a corresponding preset electrical parameter threshold during the operation of the functional motor, including:

[0080] At least one bus voltage parameter is obtained, and it is determined whether the at least one bus voltage parameter is greater than or equal to the corresponding preset electrical parameter threshold.

[0081] Optionally, the electrical parameters include conduction phase voltage parameters;

[0082] The conduction phase voltage parameters include conduction phase voltage drop, conduction phase voltage drop difference and conduction phase voltage drop change rate;

[0083] The conduction phase voltage drop refers to the relative value of the conduction phase voltage change of the functional motor within one commutation cycle;

[0084] The conduction phase voltage drop difference refers to the difference in conduction phase voltage drops corresponding to different commutation cycles of the functional motor;

[0085] The conduction phase voltage drop change rate is used to characterize the change trend of the conduction phase voltage drop of the functional motor;

[0086] The overload identification unit determines whether the electrical parameter is greater than or equal to a corresponding preset electrical parameter threshold during the operation of the functional motor, including:

[0087] At least one conducting phase voltage parameter is obtained, and it is determined whether the at least one conducting phase voltage parameter is greater than or equal to the corresponding preset electrical parameter threshold.

[0088] Optionally, the electrical parameters include a freewheeling time parameter;

[0089] The freewheeling time parameters include the freewheeling time, the freewheeling time difference and the freewheeling time change rate when the functional motor is commutated;

[0090] The freewheeling time difference refers to the difference in freewheeling time corresponding to different commutation cycles of the functional motor;

[0091] The freewheeling time change rate is used to characterize the change trend of the freewheeling time of the functional motor;

[0092] The overload identification unit determines whether the electrical parameter is greater than or equal to a corresponding preset electrical parameter threshold during the operation of the functional motor, including:

[0093] At least one freewheeling time parameter is obtained, and it is determined whether the at least one freewheeling time parameter is greater than or equal to the corresponding preset electrical parameter threshold.

[0094] Optionally, the overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including:

[0095] In response to the power parameter not matching the first control strategy, the overload identification unit is configured to select the power parameter as the target operating parameter;

[0096] The overload identification unit is further configured to monitor the power parameter and determine whether the functional motor enters an overload state according to the power parameter and / or a change in the power parameter.

[0097] Optionally, the overload identification unit monitors the power parameter and determines whether the functional motor enters an overload state according to the power parameter and / or a change in the power parameter, including:

[0098] During operation of the functional motor, determining whether the power parameter is greater than or equal to a corresponding preset power parameter threshold;

[0099] In response to the power parameter being greater than or equal to the corresponding preset power parameter threshold, it is determined that the functional motor enters a heavy load state.

[0100] Optionally, the power parameters include motor power, motor power difference and motor power change rate;

[0101] The motor power difference refers to the difference between the motor power of the functional motor at two adjacent moments;

[0102] The motor power change rate is used to characterize the change trend of the motor power of the functional motor at a corresponding moment;

[0103] The overload identification unit determines whether the power parameter is greater than or equal to a corresponding preset motor power parameter threshold during the operation of the functional motor, including:

[0104] At least one power parameter is obtained, and it is determined whether the at least one power parameter is greater than or equal to a corresponding preset power parameter threshold.

[0105] Optionally, the overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including:

[0106] In response to the torque parameter not matching the first control strategy, the heavy load identification unit is configured to select the torque parameter as the target operating parameter;

[0107] The overload identification unit is further configured to monitor the torque parameter and determine whether the functional motor enters an overload state based on the torque parameter and / or a change in the torque parameter.

[0108] Optionally, the overload identification unit monitors the torque parameter and determines whether the functional motor enters an overload state according to the torque parameter and / or a change in the torque parameter, including:

[0109] During operation of the functional motor, determining whether the torque parameter is greater than or equal to a corresponding preset torque parameter threshold;

[0110] In response to the torque parameter being greater than or equal to the corresponding preset torque parameter threshold, it is determined that the functional motor enters a heavy load state.

[0111] Optionally, the torque parameters include motor torque, motor torque difference and motor torque change rate;

[0112] The motor torque difference refers to the difference between the motor torques of the functional motor at two adjacent moments;

[0113] The motor torque change rate is used to characterize the change trend of the motor torque of the functional motor at a corresponding moment;

[0114] The overload identification unit determines whether the torque parameter is greater than or equal to a corresponding preset torque parameter threshold during the operation of the functional motor, including:

[0115] At least one torque parameter is obtained, and it is determined whether the at least one torque parameter is greater than or equal to a corresponding preset torque parameter threshold.

[0116] Optionally, the overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including:

[0117] In response to the PWM duty cycle parameter not matching the first control strategy, the overload identification unit is configured to select the PWM duty cycle parameter as the target operating parameter;

[0118] The overload identification unit is further configured to monitor the PWM duty cycle parameter and determine whether the functional motor enters an overload state according to the PWM duty cycle parameter and / or a change in the PWM duty cycle parameter.

[0119] Optionally, the overload identification unit monitors the PWM duty cycle parameter and determines whether the functional motor enters an overload state according to the PWM duty cycle parameter and / or a change in the PWM duty cycle parameter, including:

[0120] During operation of the functional motor, determining whether the PWM duty cycle parameter is greater than or equal to a corresponding preset duty cycle parameter threshold;

[0121] In response to the PWM duty cycle parameter being greater than or equal to the corresponding preset duty cycle parameter threshold, it is determined that the functional motor enters a heavy load state.

[0122] Optionally, the PWM duty cycle parameters include the duty cycle, duty cycle difference and duty cycle change rate of the corresponding control signal of the functional motor;

[0123] The duty cycle difference refers to the difference between the duty cycles of the functional motor at two adjacent moments;

[0124] The duty cycle change rate is used to characterize the change trend of the duty cycle of the functional motor at a corresponding moment;

[0125] The overload identification unit determines whether the duty cycle parameter is greater than or equal to a corresponding preset duty cycle parameter threshold during the operation of the functional motor, including:

[0126] At least one PWM duty cycle parameter is obtained, and it is determined whether the at least one PWM duty cycle parameter is greater than or equal to a corresponding preset duty cycle parameter threshold.

[0127] Optionally, the overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including:

[0128] In response to the rotational speed parameter and the electrical parameter not matching the first control strategy, the overload identification unit is configured to select the rotational speed parameter and the electrical parameter as the target operating parameter;

[0129] The overload identification unit is further configured to monitor the speed parameter and the electrical parameter, determine the flow ratio parameter based on the ratio of the electrical parameter to the speed parameter, and determine whether the functional motor enters an overload state based on the flow ratio parameter and / or changes in the flow ratio parameter.

[0130] Optionally, the speed parameter includes a motor speed parameter, and the flow ratio parameter represents a ratio of the electrical parameter to the motor speed parameter;

[0131] The overload identification unit determines whether the functional motor enters an overload state according to the flow ratio parameter and / or a change in the flow ratio parameter, including:

[0132] During operation of the functional motor, determining whether the flow ratio parameter is greater than or equal to a corresponding preset flow ratio parameter threshold;

[0133] In response to the flow ratio parameter being greater than or equal to the corresponding preset flow ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

[0134] Optionally, the speed parameter includes a motor sector time parameter, and the flow ratio parameter represents a ratio of the electrical parameter to the motor sector time parameter;

[0135] The overload identification unit determines whether the functional motor enters an overload state according to the flow ratio parameter and / or a change in the flow ratio parameter, including:

[0136] During operation of the functional motor, determining whether the flow ratio parameter is less than or equal to a corresponding preset flow ratio parameter threshold;

[0137] In response to the flow ratio parameter being less than or equal to the corresponding preset flow ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

[0138] Optionally, the turnover ratio parameters include turnover ratio, turnover ratio difference and turnover ratio change rate;

[0139] Wherein, the flow ratio refers to the ratio of the electrical parameter to the speed parameter;

[0140] The turnover ratio difference refers to the difference between the turnover ratios at two adjacent moments;

[0141] The turnover ratio change rate is used to characterize the change trend of the turnover ratio at a corresponding moment;

[0142] The overload identification unit determines whether the flow ratio parameter is greater than or equal to the corresponding preset flow ratio parameter threshold during the operation of the functional motor, including:

[0143] At least one turnover ratio parameter is obtained, and it is determined whether the at least one turnover ratio parameter is greater than or equal to a corresponding preset turnover ratio parameter threshold.

[0144] Optionally, the overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including:

[0145] In response to the speed parameter and the power parameter not matching the first control strategy, the overload identification unit is configured to select the speed parameter and the power parameter as the target operating parameter;

[0146] The overload identification unit is further configured to monitor the speed parameter and the power parameter, determine the power-to-speed ratio parameter based on the ratio of the power parameter to the speed parameter, and determine whether the functional motor enters an overload state based on the power-to-speed ratio parameter and / or changes in the power-to-speed ratio parameter.

[0147] Optionally, the speed parameter includes a motor speed parameter, and the power-to-conversion ratio parameter represents a ratio of the power parameter to the motor speed parameter;

[0148] The overload identification unit determines whether the functional motor enters an overload state according to the power-to-conversion ratio parameter and / or a change in the power-to-conversion ratio parameter, including:

[0149] During operation of the functional motor, determining whether the power-to-conversion ratio parameter is greater than or equal to a corresponding preset power-to-conversion ratio parameter threshold;

[0150] In response to the power-to-conversion ratio parameter being greater than or equal to the corresponding preset power-to-conversion ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

[0151] Optionally, the speed parameter includes a motor sector time parameter, and the power-to-conversion ratio parameter represents a ratio of the power parameter to the motor sector time parameter;

[0152] The overload identification unit determines whether the functional motor enters an overload state according to the power-to-conversion ratio parameter and / or a change in the power-to-conversion ratio parameter, including:

[0153] During operation of the functional motor, determining whether the power-to-conversion ratio parameter is less than or equal to a corresponding preset power-to-conversion ratio parameter threshold;

[0154] In response to the power-to-conversion ratio parameter being less than or equal to the corresponding preset power-to-conversion ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

[0155] Optionally, the power conversion ratio parameters include power conversion ratio, power conversion ratio difference and power conversion ratio change rate;

[0156] The power-to-conversion ratio refers to the ratio of the power parameter to the speed parameter;

[0157] The power-to-conversion ratio difference refers to the difference between the power-to-conversion ratio at two adjacent moments;

[0158] The power-to-conversion ratio change rate is used to characterize the change trend of the power-to-conversion ratio at a corresponding moment;

[0159] The overload identification unit determines whether the power-to-conversion ratio parameter is greater than or equal to the corresponding preset power-to-conversion ratio parameter threshold during the operation of the functional motor, including:

[0160] At least one power-to-conversion ratio parameter is obtained, and it is determined whether the at least one power-to-conversion ratio parameter is greater than or equal to a corresponding preset power-to-conversion ratio parameter threshold.

[0161] Optionally, the overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including:

[0162] In response to the speed parameter and the torque parameter not matching the first control strategy, the overload identification unit is configured to select the speed parameter and the torque parameter as the target operating parameter;

[0163] The overload identification unit is further configured to monitor the speed parameter and the torque parameter, determine the torque-to-speed ratio parameter based on the ratio of the torque parameter to the speed parameter, and determine whether the functional motor enters an overload state based on the torque-to-speed ratio parameter and / or changes in the torque-to-speed ratio parameter.

[0164] Optionally, the speed parameter includes a motor speed parameter, and the torque-to-torque ratio parameter represents a ratio of the torque parameter to the motor speed parameter;

[0165] The overload identification unit determines whether the functional motor enters an overload state according to the torque-to-turn ratio parameter and / or a change in the torque-to-turn ratio parameter, including:

[0166] During operation of the functional motor, determining whether the torque-to-turn ratio parameter is greater than or equal to a corresponding preset torque-to-turn ratio parameter threshold;

[0167] In response to the torque-to-turn ratio parameter being greater than or equal to the corresponding preset torque-to-turn ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

[0168] Optionally, the speed parameter includes a motor sector time parameter, and the torque-to-turn ratio parameter represents a ratio of the torque parameter to the motor sector time parameter;

[0169] The overload identification unit determines whether the functional motor enters an overload state according to the torque-to-turn ratio parameter and / or a change in the torque-to-turn ratio parameter, including:

[0170] During operation of the functional motor, determining whether the torque-to-turn ratio parameter is less than or equal to a corresponding preset torque-to-turn ratio parameter threshold;

[0171] In response to the torque-to-turn ratio parameter being less than or equal to the corresponding preset torque-to-turn ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

[0172] Optionally, the torque-to-turn ratio parameters include the torque-to-turn ratio, the torque-to-turn ratio difference and the torque-to-turn ratio change rate;

[0173] Wherein, the torque-to-speed ratio refers to the ratio of the torque parameter to the speed parameter;

[0174] The torque-to-turn ratio difference refers to the difference between the torque-to-turn ratio at two adjacent moments;

[0175] The torque-to-turn ratio change rate is used to characterize the change trend of the torque-to-turn ratio at a corresponding moment;

[0176] The overload identification unit determines whether the torque-to-turn ratio parameter is greater than or equal to the corresponding preset torque-to-turn ratio parameter threshold during the operation of the functional motor, including:

[0177] At least one torque-to-turn ratio parameter is obtained, and it is determined whether the at least one torque-to-turn ratio parameter is greater than or equal to a corresponding preset torque-to-turn ratio parameter threshold.

[0178] Optionally, the overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including:

[0179] In response to the speed parameter and the PWM duty cycle parameter not matching the first control strategy, the overload identification unit is configured to select the speed parameter and the PWM duty cycle parameter as the target operating parameter;

[0180] The overload identification unit is further configured to monitor the speed parameter and the PWM duty cycle parameter, determine the idling ratio parameter based on the ratio of the PWM duty cycle parameter to the speed parameter, and determine whether the functional motor enters an overload state based on the idling ratio parameter and / or changes in the idling ratio parameter.

[0181] Optionally, the speed parameter includes a motor speed parameter, and the idling ratio parameter represents a ratio of the PWM duty cycle parameter to the motor speed parameter;

[0182] The overload identification unit determines whether the functional motor enters an overload state according to the idling ratio parameter and / or a change in the idling ratio parameter, including:

[0183] During the operation of the functional motor, determining whether the idling ratio parameter is greater than or equal to a corresponding preset idling ratio parameter threshold;

[0184] In response to the idle ratio parameter being greater than or equal to the corresponding preset idle ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

[0185] Optionally, the speed parameter includes a motor sector time parameter, and the idling ratio parameter represents a ratio of the PWM duty cycle parameter to the motor sector time parameter;

[0186] The overload identification unit determines whether the functional motor enters an overload state according to the idling ratio parameter and / or a change in the idling ratio parameter, including:

[0187] During operation of the functional motor, determining whether the idling ratio parameter is less than or equal to a corresponding preset idling ratio parameter threshold;

[0188] In response to the idle ratio parameter being less than or equal to the corresponding preset idle ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

[0189] Optionally, the idle ratio parameters include the idle ratio, the idle ratio difference and the idle ratio change rate;

[0190] Wherein, the idling ratio refers to the ratio of the PWM duty cycle parameter to the speed parameter;

[0191] The idling ratio difference refers to the difference between the idling ratios at two adjacent moments;

[0192] The idling ratio change rate is used to represent the change trend of the idling ratio at a corresponding moment;

[0193] The overload identification unit determines whether the idling ratio parameter is greater than or equal to the corresponding preset idling ratio parameter threshold during the operation of the functional motor, including:

[0194] At least one idle ratio parameter is obtained, and it is determined whether the at least one idle ratio parameter is greater than or equal to a corresponding preset idle ratio parameter threshold.

[0195] Optionally, the overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including:

[0196] In response to the electrical parameter and the PWM duty cycle parameter not matching the first control strategy, the overload identification unit is configured to select the electrical parameter and the PWM duty cycle parameter as the target operating parameter;

[0197] The overload identification unit is further configured to monitor the electrical parameters and the PWM duty cycle parameters, determine the empty-to-electric ratio parameters based on the ratio of the PWM duty cycle parameters to the electrical parameters, and determine whether the functional motor enters an overload state based on the empty-to-electric ratio parameters and / or changes in the empty-to-electric ratio parameters.

[0198] Optionally, the overload identification unit determines whether the functional motor enters an overload state according to the air-to-electricity ratio parameter and / or a change in the air-to-electricity ratio parameter, including:

[0199] During the operation of the functional motor, determining whether the air-to-electricity ratio parameter is greater than or equal to a corresponding preset air-to-electricity ratio parameter threshold;

[0200] In response to the air-to-electricity ratio parameter being greater than or equal to the corresponding preset air-to-electricity ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

[0201] Optionally, the air-to-electricity ratio parameters include the air-to-electricity ratio, the air-to-electricity ratio difference and the air-to-electricity ratio change rate;

[0202] Wherein, the air-to-electric ratio refers to the ratio of the PWM duty cycle parameter to the electrical parameter;

[0203] The air-to-electricity ratio difference refers to the difference between the air-to-electricity ratio at two adjacent moments;

[0204] The air-to-electricity ratio change rate is used to characterize the change trend of the air-to-electricity ratio at a corresponding moment;

[0205] The overload identification unit, during the operation of the functional motor, determines whether the air-to-electricity ratio parameter is greater than or equal to the corresponding preset air-to-electricity ratio parameter threshold, including:

[0206] At least one air-to-electricity ratio parameter is obtained, and it is determined whether the at least one air-to-electricity ratio parameter is greater than or equal to a corresponding preset air-to-electricity ratio parameter threshold.

[0207] Optionally, the overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including:

[0208] In response to the power parameter and the PWM duty cycle parameter not matching the first control strategy, the overload identification unit is configured to select the power parameter and the PWM duty cycle parameter as the target operating parameter;

[0209] The overload identification unit is further configured to monitor the power parameter and the PWM duty cycle parameter, determine the idle power ratio parameter based on the ratio of the PWM duty cycle parameter to the power parameter, and determine whether the functional motor enters an overload state based on the idle power ratio parameter and / or changes in the idle power ratio parameter.

[0210] Optionally, the overload identification unit determines whether the functional motor enters an overload state according to the idle power ratio parameter and / or a change in the idle power ratio parameter, including:

[0211] During the operation of the functional motor, determining whether the idle power ratio parameter is greater than or equal to a corresponding preset idle power ratio parameter threshold;

[0212] In response to the idle power ratio parameter being greater than or equal to the corresponding preset idle power ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

[0213] Optionally, the air-work ratio parameters include air-work ratio, air-work ratio difference and air-work ratio change rate;

[0214] The idle power ratio refers to the ratio of the PWM duty cycle parameter to the power parameter;

[0215] The air-work ratio difference refers to the difference between the air-work ratios at two adjacent moments;

[0216] The air-power ratio change rate is used to characterize the change trend of the air-power ratio at a corresponding moment;

[0217] The overload identification unit determines whether the idle power ratio parameter is greater than or equal to the corresponding preset idle power ratio parameter threshold during the operation of the functional motor, including:

[0218] At least one air-power ratio parameter is obtained, and it is determined whether the at least one air-power ratio parameter is greater than or equal to a corresponding preset air-power ratio parameter threshold.

[0219] Optionally, the overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including:

[0220] In response to the torque parameter and the PWM duty cycle parameter not matching the first control strategy, the overload identification unit is configured to select the torque parameter and the PWM duty cycle parameter as the target operating parameter;

[0221] The overload identification unit is further configured to monitor the torque parameter and the PWM duty cycle parameter, determine the air-torque ratio parameter based on the ratio of the PWM duty cycle parameter to the torque parameter, and determine whether the functional motor enters an overload state based on the air-torque ratio parameter and / or changes in the air-torque ratio parameter.

[0222] Optionally, the overload identification unit determines whether the functional motor enters an overload state according to the air-torque ratio parameter and / or a change in the air-torque ratio parameter, including:

[0223] During the operation of the functional motor, determining whether the air-torque ratio parameter is greater than or equal to a corresponding preset air-torque ratio parameter threshold;

[0224] In response to the air-torque ratio parameter being greater than or equal to the corresponding preset air-torque ratio parameter threshold, it is determined that the functional motor enters a heavy-load state.

[0225] Optionally, the space-to-moment ratio parameters include space-to-moment ratio, space-to-moment ratio difference and space-to-moment ratio change rate;

[0226] Wherein, the air-torque ratio refers to the ratio of the PWM duty cycle parameter to the torque parameter;

[0227] The space-to-moment ratio difference refers to the difference between the space-to-moment ratios at two adjacent moments;

[0228] The space-to-moment ratio change rate is used to characterize the change trend of the space-to-moment ratio at a corresponding moment;

[0229] The overload identification unit determines whether the air-torque ratio parameter is greater than or equal to the corresponding preset air-torque ratio parameter threshold during the operation of the functional motor, including:

[0230] At least one space-to-moment ratio parameter is obtained, and it is determined whether the at least one space-to-moment ratio parameter is greater than or equal to a corresponding preset space-to-moment ratio parameter threshold.

[0231] Optionally, in response to the second control strategy being the same as the first control strategy, the overload control unit selects the second control strategy from the plurality of control strategies, and performs control adjustment on the functional motor based on the second control strategy, including:

[0232] The overload control unit controls the operating parameter corresponding to the second control strategy to be reduced to a target value, and the target value is smaller than the value of the operating parameter corresponding to the second control strategy when the functional motor is in a normal operating state.

[0233] Optionally, in response to the second control strategy being different from the first control strategy, the overload control unit selects the second control strategy from the plurality of control strategies, and performs control adjustment on the functional motor based on the second control strategy, including:

[0234] The overload control unit controls the operating parameter corresponding to the second control strategy to be reduced to a target value, and the target value is less than or equal to an upper limit threshold of the operating parameter corresponding to the second control strategy when the functional motor is in normal operation.

[0235] On the other hand, the embodiments of this specification further provide an electric gardening vehicle, comprising:

[0236] Frame;

[0237] a functional mechanism attached to the vehicle frame, comprising a functional motor and an output assembly driven by the functional motor to perform a specific functional operation;

[0238] A controller component, used to control the operating state of the functional motor;

[0239] The functional motor has a plurality of operating parameters, and the controller component has a plurality of control strategies corresponding to the plurality of operating parameters for the functional motor;

[0240] The controller assembly includes a heavy load identification unit and a heavy load control unit;

[0241] The overload identification unit is configured to select a target operating parameter from the plurality of operating parameters for monitoring, and determine whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter;

[0242] wherein the target operating parameter does not match a first control strategy currently adopted by the controller component for the functional motor;

[0243] In response to determining that the functional motor enters the overload state, the overload control unit is configured to select a second control strategy from the multiple control strategies, and control and adjust the functional motor based on the second control strategy to make it exit the overload state.

[0244] In another aspect, an embodiment of the present specification further provides an electric riding lawn mower, comprising:

[0245] Frame;

[0246] A carrying mechanism, provided on the frame, for carrying a user;

[0247] a mowing mechanism attached to the vehicle frame, comprising a mowing motor and a cutter assembly driven by the mowing motor to perform a mowing operation;

[0248] A controller component, used for controlling the operating state of the mowing motor;

[0249] The mowing motor has a plurality of operating parameters, and the controller component has a plurality of control strategies corresponding to the plurality of operating parameters for the mowing motor;

[0250] The controller assembly includes a heavy load identification unit and a heavy load control unit;

[0251] The overload identification unit is configured to select a target operating parameter from the plurality of operating parameters for monitoring, and determine whether the mowing motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter;

[0252] wherein the target operating parameter does not match a first control strategy currently adopted by the controller component for the mowing motor;

[0253] In response to determining that the functional motor enters the overload state, the overload control unit is configured to select a second control strategy from the multiple control strategies, and adjust the control of the mowing motor based on the second control strategy to make it exit the overload state.

[0254] As can be seen from the above, the electric work vehicle, electric garden work vehicle, and electric riding lawn mower provided by one or more optional embodiments of this specification have the following beneficial technical effects:

[0255] In the electric work vehicle, electric garden work vehicle and electric riding lawn mower, the overload identification unit in the controller component monitors one or more operating parameters related to the functional motor, and determines whether the functional motor has entered an overload state based on the operating parameters and / or changes in the operating parameters. When it is determined that the functional motor has entered an overload state, the overload control unit in the controller component selects an appropriate control strategy according to the situation to adjust and control the functional motor in a timely manner, so that the functional motor exits the overload state. In this way, it is possible to accurately and sensitively identify sudden changes in the overload of the motor, further quickly respond to sudden changes in the overload, adjust the control strategy in a timely manner, and maintain the motor system in a normal operating state, thereby improving the stability and work efficiency of the entire machine and optimizing the user experience. [Brief Description of the Drawings]

[0256] The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the present invention in any way. In the accompanying drawings:

[0257] FIG1 is a circuit diagram corresponding to a first electric working vehicle provided in an optional embodiment of this specification;

[0258] FIG2 is a circuit diagram corresponding to a second electric working vehicle provided in an optional embodiment of this specification;

[0259] FIG3 is a module diagram corresponding to an electric work vehicle provided in an optional embodiment of this specification;

[0260] FIG4 is a schematic diagram of a sector time provided in an optional embodiment of this specification;

[0261] FIG5 is a flow chart corresponding to the first electric working vehicle provided in an optional embodiment of this specification;

[0262] FIG6 is a flow chart corresponding to a second electric working vehicle provided in an optional embodiment of this specification;

[0263] FIG7 is a flowchart corresponding to a third electric working vehicle provided in an optional embodiment of this specification;

[0264] FIG8 is a flowchart corresponding to the fourth electric working vehicle provided in an optional embodiment of this specification. ;

[0265] FIG9 is a curve diagram corresponding to the first electric working vehicle provided in an optional embodiment of this specification;

[0266] FIG10 is a curve diagram corresponding to a second electric working vehicle provided in an optional embodiment of this specification;

[0267] FIG11 is a curve diagram corresponding to a third electric working vehicle provided in an optional embodiment of this specification;

[0268] FIG12 is a curve diagram corresponding to the fourth electric working vehicle provided in an optional embodiment of this specification;

[0269] FIG13 is a curve diagram corresponding to a third electric working vehicle provided in an optional embodiment of this specification;

[0270] FIG14 is a curve diagram corresponding to the fourth electric working vehicle provided in an optional embodiment of this specification;

[0271] FIG15 is a schematic structural diagram of an electric work vehicle provided in an optional embodiment of this specification;

[0272] FIG16 is another structural diagram of an electric work vehicle provided in an optional embodiment of this specification;

[0273] FIG17 is a functional block diagram of a control component in an electric work vehicle provided in an optional embodiment of this specification;

[0274] FIG18 is a schematic diagram of a method for selecting a speed parameter as a target operating parameter for overload determination by a heavy load identification unit in an electric work vehicle provided in an optional embodiment of this specification;

[0275] FIG19 is a schematic diagram of a method for determining overload by selecting motor speed parameters for a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification;

[0276] FIG20 is a schematic diagram of a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification for determining a sudden heavy load change based on a motor speed threshold;

[0277] FIG21 is a schematic diagram of a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification for determining a sudden heavy load change based on a motor speed difference threshold;

[0278] FIG22 is a schematic diagram showing a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present invention for determining a sudden heavy load change based on a motor speed change rate threshold;

[0279] FIG23 is a schematic diagram of a method for determining overload by using motor sector time parameters in a heavy load identification unit of an electric work vehicle according to an optional embodiment of the present specification;

[0280] FIG24 is a schematic diagram showing a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification that determines a sudden heavy load change based on a motor sector time threshold;

[0281] FIG25 is a schematic diagram of a heavy load identification unit in an electric working vehicle according to an optional embodiment of the present specification, which determines a sudden heavy load change based on a motor sector time difference threshold;

[0282] FIG26 is a schematic diagram of a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification, which determines a sudden heavy load change based on a motor sector time change rate threshold;

[0283] FIG27 is a schematic diagram of a method for selecting electrical parameters as target operating parameters for overload determination by a heavy load identification unit in an electric work vehicle provided in an optional embodiment of this specification;

[0284] FIG28 is a schematic diagram of a method for determining overload based on electrical parameters by a overload identification unit in an electric work vehicle according to an optional embodiment of the present specification;

[0285] FIG29 is a schematic diagram showing a heavy load identification unit in an electric working vehicle according to an optional embodiment of the present specification, which determines a sudden heavy load change based on a bus current threshold;

[0286] FIG30 is a schematic diagram of a heavy load identification unit in an electric working vehicle according to an optional embodiment of the present specification for determining a sudden heavy load change based on a bus current difference threshold;

[0287] FIG31 is a schematic diagram of a heavy load identification unit in an electric working vehicle according to an optional embodiment of the present specification for determining a sudden heavy load change based on a bus current change rate threshold;

[0288] FIG32 is a schematic diagram showing a heavy load identification unit in an electric working vehicle according to an optional embodiment of the present specification, which determines a sudden heavy load change based on a bus voltage drop threshold;

[0289] FIG33 is a schematic diagram of a heavy load identification unit in an electric working vehicle according to an optional embodiment of the present specification for determining a sudden heavy load change based on a conduction phase voltage drop threshold;

[0290] FIG34 is a schematic diagram of the freewheeling time of a functional motor of an electric working vehicle provided in an optional embodiment of this specification during operation;

[0291] FIG35 is a schematic diagram of a method for selecting a power parameter as a target operating parameter for overload determination by a heavy load identification unit in an electric work vehicle provided in an optional embodiment of this specification;

[0292] FIG36 is a schematic diagram of a method for determining overload based on power parameters by a overload identification unit in an electric work vehicle according to an optional embodiment of this specification;

[0293] FIG37 is a schematic diagram of a method for selecting a torque parameter as a target operating parameter for overload determination by a heavy load identification unit in an electric work vehicle according to an optional embodiment of this specification;

[0294] FIG38 is a schematic diagram of a method for determining overload based on torque parameters by a overload identification unit in an electric work vehicle according to an optional embodiment of this specification;

[0295] FIG39 is a schematic diagram of a method for selecting a PWM duty cycle parameter as a target operating parameter for overload determination by a heavy load identification unit in an electric working vehicle provided in an optional embodiment of this specification;

[0296] FIG40 is a schematic diagram of a method for determining a heavy load based on a PWM duty cycle parameter by a heavy load identification unit in an electric working vehicle according to an optional embodiment of the present specification;

[0297] FIG41 is a schematic diagram of a method for selecting a speed parameter and an electrical parameter as target operating parameters for overload determination by a heavy load identification unit in an electric work vehicle provided in an optional embodiment of this specification;

[0298] FIG42 is a schematic diagram of a method for determining overload based on motor speed parameters and electrical parameters by a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification;

[0299] FIG43 is a schematic diagram showing a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification that determines a sudden change in heavy load based on a turnover ratio threshold;

[0300] FIG44 is a schematic diagram of a method for determining overload based on motor sector time parameters and electrical parameters by a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification;

[0301] FIG45 is another schematic diagram of a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification determining a sudden change in heavy load based on a turnover ratio threshold;

[0302] FIG46 is a schematic diagram showing a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification, which determines a sudden heavy load change based on a flow ratio difference threshold;

[0303] FIG47 is another schematic diagram of a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification determining a sudden heavy load change based on a flow ratio difference threshold;

[0304] FIG48 is a schematic diagram showing a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification, which determines a sudden heavy load change based on a turnover ratio change rate threshold;

[0305] FIG49 is another schematic diagram of a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification, which determines a sudden heavy load change based on a turnover ratio change rate threshold;

[0306] FIG50 is a schematic diagram of a method for selecting a speed parameter and a power parameter as target operating parameters for overload determination by a heavy load identification unit in an electric work vehicle provided in an optional embodiment of this specification;

[0307] FIG51 is a schematic diagram of a method for determining overload based on motor speed parameters and power parameters by a heavy load identification unit in an electric work vehicle according to an optional embodiment of this specification;

[0308] FIG52 is a schematic diagram of a method for determining overload based on motor sector time parameters and power parameters by a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification;

[0309] FIG53 is a schematic diagram of a method for selecting a speed parameter and a torque parameter as target operating parameters for overload determination by a heavy load identification unit in an electric work vehicle provided in an optional embodiment of this specification;

[0310] FIG54 is a schematic diagram of a method for determining overload based on motor speed parameters and torque parameters by a heavy load identification unit in an electric work vehicle according to an optional embodiment of this specification;

[0311] FIG55 is a schematic diagram of a method for determining overload based on motor sector time parameters and torque parameters by a heavy load identification unit in an electric work vehicle according to an optional embodiment of the present specification;

[0312] FIG56 is a schematic diagram of a method for selecting a speed parameter and a PWM duty cycle parameter as target operating parameters for overload determination by a heavy load identification unit in an electric working vehicle provided in an optional embodiment of this specification;

[0313] FIG57 is a schematic diagram of a method for determining a heavy load based on a motor speed parameter and a PWM duty cycle parameter by a heavy load identification unit in an electric working vehicle according to an optional embodiment of the present specification;

[0314] FIG58 is a schematic diagram of a method for determining overload based on motor sector time parameters and PWM duty cycle parameters by a heavy load identification unit in an electric working vehicle according to an optional embodiment of the present specification;

[0315] FIG59 is a schematic diagram of a method for selecting electrical parameters and PWM duty cycle parameters as target operating parameters for overload determination by a heavy load identification unit in an electric work vehicle provided in an optional embodiment of this specification;

[0316] FIG60 is a schematic diagram of a method for determining a heavy load based on an air-to-electricity ratio by a heavy load identification unit in an electric work vehicle according to an optional embodiment of this specification;

[0317] FIG61 is a schematic diagram of a method for selecting a power parameter and a PWM duty cycle parameter as target operating parameters for overload determination by a heavy load identification unit in an electric work vehicle according to an optional embodiment of this specification;

[0318] FIG62 is a schematic diagram of a method for determining a heavy load based on the idle-power ratio by a heavy load identification unit in an electric work vehicle according to an optional embodiment of this specification;

[0319] FIG63 is a schematic diagram of a method for selecting a torque parameter and a PWM duty cycle parameter as target operating parameters for overload determination by a heavy load identification unit in an electric working vehicle according to an optional embodiment of this specification;

[0320] FIG64 is a schematic diagram of a method for determining a heavy load based on the air-to-moment ratio by a heavy load identification unit in an electric work vehicle according to an optional embodiment of this specification;

[0321] [Corrected 24.07.2024 in accordance with Rule 26] Figure 65 is a logic block diagram of PWM duty cycle open-loop control for a functional motor in an electric working vehicle provided in an optional embodiment of this specification;

[0322] FIG66 is a schematic diagram of a heavy-load control unit in an electric work vehicle according to an optional embodiment of the present specification reducing a duty cycle in a linear decreasing manner;

[0323] FIG67 is a schematic diagram of a heavy-load control unit in an electric work vehicle according to an optional embodiment of the present specification, wherein the duty cycle is reduced by a curve reduction method;

[0324] FIG68 is a schematic diagram showing bus current changes when a heavy-load control unit in an electric working vehicle switches from a PWM duty cycle open-loop control strategy to a current closed-loop control strategy according to an optional embodiment of this specification;

[0325] FIG69 is a schematic diagram illustrating the change in motor speed when the heavy-duty control unit in the electric working vehicle switches from a PWM duty cycle open-loop control strategy to a speed closed-loop control strategy according to an optional embodiment of this specification;

[0326] FIG70 is a schematic diagram illustrating the change in motor power when the heavy-load control unit in the electric working vehicle switches from a PWM duty cycle open-loop control strategy to a power closed-loop control strategy provided in an optional embodiment of this specification;

[0327] FIG71 is a schematic diagram showing the change in motor torque when the heavy-load control unit in the electric working vehicle switches from a PWM duty cycle open-loop control strategy to a torque closed-loop control strategy provided in an optional embodiment of this specification;

[0328] FIG72 is a logic block diagram of a speed closed-loop control for a functional motor in an electric working vehicle provided in an optional embodiment of this specification;

[0329] FIG73 is a schematic diagram of a heavy-load control unit in an electric work vehicle according to an optional embodiment of the present specification reducing the motor speed in a linear decreasing manner;

[0330] FIG74 is a schematic diagram of a heavy-load control unit in an electric work vehicle according to an optional embodiment of the present specification using a curve reduction method to reduce the motor speed;

[0331] FIG75 is a schematic diagram showing bus current changes when the heavy-load control unit in the electric work vehicle switches from a speed closed-loop control strategy to a current closed-loop control strategy according to an optional embodiment of this specification;

[0332] FIG76 is a schematic diagram showing the duty cycle change when the heavy-load control unit in the electric working vehicle switches from a speed closed-loop control strategy to a PWM duty cycle open-loop control strategy according to an optional embodiment of this specification;

[0333] FIG77 is a schematic diagram showing the change in motor power when the heavy-load control unit in the electric work vehicle switches from a speed closed-loop control strategy to a power closed-loop control strategy according to an optional embodiment of this specification;

[0334] Figure 78 is a schematic diagram of the change in motor torque when the heavy-load control unit in the electric work vehicle provided in an optional embodiment of this specification switches from a speed closed-loop control strategy to a torque closed-loop control strategy. [Specific implementation method]

[0335] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0336] Compared with traditional fuel-powered lawn mowers, rechargeable lawn mowers have the advantages of all-weather zero emissions, zero fuel consumption, low noise, and simple maintenance (no gasoline, no engine oil, no air filter, no spark plugs, no fuel storage, etc.). In rechargeable lawn mowers, the power system uses an electric motor instead of a fuel engine, and the drive wheel motors can be controlled separately to achieve straight-ahead, reverse, turning, zero-turn and other motion control of the entire vehicle, reducing the structural complexity of the entire vehicle and making the control of the entire vehicle more flexible.

[0337] During operation, the load of the mowing motor fluctuates greatly. When the grass is short and sparse, the load is very small. When the grass is dense, the load becomes very large. In actual operation, the change from low-groomed grass to dense grass is not necessarily gradual, but may be sudden. Suddenly, the motor goes from low-groomed grass to dense grass, which suddenly becomes a heavy load for the motor. On the other hand, after long-term operation, the cutting table will inevitably accumulate a large amount of grass debris. This grass debris mixes with the newly cut dense grass, increasing the load of the entire machine. Continuous operation in the heavy load range will make the system extremely sensitive to sudden changes in load. It is common that under such conditions, even a slight increase in load will trigger the system's overload protection.

[0338] If the protection current threshold set by the controller is relatively large or the delay time is relatively long, the power device may easily burn out after operating beyond its safe operating area (SOA) for a long time due to protection lag. The most typical example is overcurrent damage. Even if the power device is not damaged, the huge stress caused by the sudden change in current is destructive to the motor body. Over time, the motor stator may burn out or the rotor magnet may be demagnetized. If the controller sets the protection current threshold to a relatively small value or the time is very short, although the protection is more sensitive and the power device is not easily damaged, it will also cause the machine to shut down very easily in the case of the above-mentioned heavy load sudden change, seriously affecting the user's working experience.

[0339] In response to the above problems, the purpose of the embodiments of this specification is to propose an electric work vehicle, an electric garden work vehicle and an electric riding lawn mower, which monitors various operating parameters associated with the motor based on a variety of control strategies that can be adopted for the motor, and determines the load changes of the motor according to the operating parameters and / or changes in the operating parameters. It can accurately and sensitively identify the sudden change of heavy load of the motor, further quickly respond to the sudden change of heavy load, adjust the control strategy in time, and maintain the motor system in normal operating state, thereby improving the stability and work efficiency of the whole machine and optimizing the user experience.

[0340] The following describes various embodiments of this specification in detail with reference to the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in the various embodiments to facilitate a better understanding of the specification. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in this specification can still be implemented.

[0341] Based on the above objectives, the embodiments of this specification provide an electric work vehicle.

[0342] Referring to Figures 1 to 3, Figure 1 is a first circuit diagram corresponding to an electric work vehicle provided in an embodiment of this specification; Figure 2 is a second circuit diagram corresponding to an electric work vehicle provided in an embodiment of this specification; and Figure 3 is a module diagram corresponding to an electric work vehicle provided in an embodiment of this specification.

[0343] In some embodiments, the electric work vehicle may include: a motor 100 .

[0344] The electric working vehicle may include: a collection module 104, the collection module 104 is used to collect at least two mechanical parameters or at least two electrical parameters of the motor 100, the mechanical parameters including a speed parameter, a sector time parameter or a torque parameter, and the electrical parameters including a bus current parameter, a phase current parameter, a bus voltage parameter, a power parameter, a freewheeling time parameter or a duty cycle parameter;

[0345] The electric work vehicle may also include: a detection module 101, which is used to process different mechanical parameters of the motor 100 according to a target calculation formula, or to process different electrical parameters of the motor 100 and generate a target value. The target calculation formula at least includes a ratio, a slope of a ratio, or a difference in a ratio, etc.

[0346] The electric work vehicle may also include: a judgment module 102 for determining whether the motor 100 is in an overloaded state based on a target value and a target preset threshold; if the target value does not meet the target preset threshold, the motor 100 is determined to be in an overloaded state, wherein the target preset threshold corresponds to the target calculation formula.

[0347] In the embodiment of this specification, the acquisition module 104 acquires the mechanical parameters or electrical parameters of the motor, which can facilitate the detection module 101 to generate a target value. The detection module 101 processes different mechanical parameters or different electrical parameters of the motor 100 according to the target calculation formula to obtain the target value, thereby facilitating the judgment module 102 to judge whether the motor 100 is in an overloaded state. The ratio of different mechanical parameters or different electrical parameters can, on the one hand, more easily provide feedback on whether the motor 100 is in an overloaded state, and on the other hand, simplify the calculation of the entire ratio, thereby releasing the computing power of the detection module 101 and providing a more accurate judgment of whether the motor 100 is in an overloaded state through the ratio of mechanical parameters to electrical parameters.

[0348] In some embodiments, the motor 100 is used to drive an electric work vehicle. Taking the electric work vehicle as a lawn mower as an example, the motor 100 can be used to drive the rotation of the cutting blade.

[0349] In some embodiments, the speed parameters include: speed, speed difference or the slope of the speed curve, the sector time parameters include: sector time, sector time difference or the slope of the sector time curve, the torque parameters include: torque, torque difference or the slope of the torque curve, the bus current parameters include: bus current, bus current difference or the slope of the bus current curve, the phase current parameters include: phase current, phase current difference or the slope of the phase current curve, the bus voltage parameters include: bus voltage, bus voltage difference or the slope of the bus voltage curve, the power parameters include: power, power difference or the slope of the power curve, the freewheeling time parameters include: freewheeling time, freewheeling time difference or the slope of the freewheeling time curve, the duty cycle parameters include: duty cycle parameters, duty cycle parameter difference or the slope of the duty cycle parameter curve, and the ratios of different mechanical parameters or the ratios of different electrical parameters are ratios of the same type.

[0350] It is understandable that the ratios of the same type here refer to the ratios of specified parameters to specified parameters, or the ratios of differences to differences, or the ratios of slopes to slopes. For example, the ratio of rotational speed to sector time, or the ratio of rotational speed difference to sector time difference, or the ratio of rotational speed slope to sector time slope, etc. The ratios of mechanical parameters to mechanical parameters can be the first mechanical parameter / the second mechanical parameter, or the second mechanical parameter / the first mechanical parameter; the ratios of different electrical parameters can also be the first electrical parameter / the second electrical parameter, or the second electrical parameter / the first electrical parameter. It should be noted that the above-mentioned first mechanical parameter, second mechanical parameter, first electrical parameter, and second electrical parameter merely refer to different parameters and do not limit the different parameters.

[0351] The following describes the various mechanical and electrical parameters.

[0352] In some embodiments, the rotational speed is: sampling the rotational speed of the motor 100 .

[0353] The speed difference is: the speed N obtained at the current moment is k Compared with the speed N obtained at the previous moment k-1 Take the difference to get ΔN k The speed difference can be an absolute value, that is, the obtained ΔN k is a positive number, which makes it easier to calculate the ratio later.

[0354] The slope of the speed curve is: Get t0, t1, t2…t k Speed ​​N0, N1, N2...N at the moment k , N0, N1, N2…N k Perform linear fitting to obtain the corresponding curve slope k, whose formula (3) is: k=(EtN–Et*EN) / [Et 2–(Et) 2 ]. Among them, EtN is the mathematical expectation of the product of sampling time t and speed, Et is the mathematical expectation of sampling time t, EN is the mathematical expectation of speed, Et 2 is the mathematical expectation of the square of the sampling time t, (Et) 2 is the square of the mathematical expectation of the sampling time t. Assume that Δt0 = t1-t0, Δt1 = t2-t1..., Δt k =t k+1 -t k In order to facilitate software calculation, it is generally designed as Δt0=Δt1=……=Δt k Therefore, the above formula can be simplified as follows: k = [N*∑(t*N)-∑t*∑N] / [N*∑t2-∑t*∑t], where N is a positive integer, * is the product of mathematical operations, Δt0, Δt1...Δt k is the time difference between two adjacent moments.

[0355] Refer to FIG. 4 , which is a schematic diagram of sector time provided in an embodiment of this specification.

[0356] In some embodiments, the sector time can be: sampling the sector time of the motor 100. It is understandable that, taking the motor 100 as a three-phase brushless DC motor 100 or a three-phase permanent magnet synchronous motor 100 as an example, one electrical cycle of the three-phase brushless DC motor 100 or the three-phase permanent magnet synchronous motor 100 is 360°, which is generally divided into 6 sectors, each sector having an electrical angle of 60°. Taking a square wave driven brushless DC motor 100 as an example, the sectors are shown in Figure 4 below. When the motor 100 is running smoothly, the time of each sector of the 360° electrical cycle (Δt0, Δt1, Δt2, Δt3, Δt4, Δt5) is relatively close. However, when the load changes drastically, the sector time will also suddenly change.

[0357] The sector time difference is: the sector time S obtained at the current moment k Compared with the sector time S obtained at the last moment k-1 Take the difference to get ΔS k The sector time difference can be an absolute value, that is, the obtained ΔS k is a positive number, which makes it easier to calculate the ratio later.

[0358] The slope of the sector time curve is: Get t0, t1, t2…t k Sector time S0, S1, S2...S k , change S0, S1, S2…S k Perform linear fitting to obtain the corresponding curve slope k, whose formula (3) is: k=(EtS-Et*ES) / [Et 2 -(Et)2 ] Where EtS is the mathematical expectation of the product of sampling time t and sector time, Et is the mathematical expectation of sampling time t, ES is the mathematical expectation of sector time, Et 2 is the mathematical expectation of the square of the sampling time t, (Et) 2 is the square of the mathematical expectation of the sampling time t. Assume that Δt0 = t1-t0, Δt1 = t2-t1..., Δt k =t k+1 -t k In order to facilitate software calculation, it is generally designed as Δt0=Δt1=……=Δt k Therefore, the above formula can be simplified to: k = [S*∑(t*S)-∑t*∑S] / [S*∑t2-∑t*∑t], where S is a positive integer, * is the product of mathematical operations, Δt0, Δt1...Δt k is the time difference between two adjacent moments.

[0359] In some embodiments, the torque may be: sampling the torque of the motor 100 .

[0360] The torque difference is: the torque A obtained at the current moment is k The torque A obtained at the previous moment k-1 Take the difference to get ΔA k The torque difference can be an absolute value, that is, the obtained ΔA k is a positive number, which makes it easier to calculate the ratio later.

[0361] The slope of the torque curve is: Get t0, t1, t2…t k The torques at the time A0, A1, A2...A k , A0, A1, A2…A k Perform linear fitting to obtain the corresponding curve slope k, whose formula (3) is: k=(EtA-Et*EA) / [Et 2 –(Et) 2 ]. Where EtA is the mathematical expectation of the product of sampling time t and torque, Et is the mathematical expectation of sampling time t, EA is the mathematical expectation of torque, Et 2 is the mathematical expectation of the square of the sampling time t, (Et) 2 is the square of the mathematical expectation of the sampling time t. Assume that Δt0 = t1-t0, Δt1 = t2-t1..., Δt k =t k+1 -t k In order to facilitate software calculation, it is generally designed as Δt0=Δt1=……=Δt k Therefore, the above formula can be simplified as follows: k=[A*∑(t*A)-∑t*∑A] / [A*∑t 2-∑t*∑t], where A is a positive integer, * is the product of mathematical operations, Δt0, Δt1…Δt k is the time difference between two adjacent moments.

[0362] In some embodiments, the bus current may be: the current flowing through Rs in FIG2 .

[0363] The bus current difference is: the bus current B obtained at the current moment is k Compared with the bus current B obtained at the previous moment k-1 Take the difference to get ΔB k The busbar current difference can be an absolute value, that is, the obtained ΔB k is a positive number, which makes it easier to calculate the ratio later.

[0364] The slope of the busbar current curve is: Get t0, t1, t2…t k The bus current B0, B1, B2...B k , B0, B1, B2…B k Perform linear fitting to obtain the corresponding curve slope k, whose formula (3) is: k=(EtB-Et*EB) / [Et 2 -(Et) 2 ]. Among them, EtB is the mathematical expectation of the product of sampling time t and bus current, Et is the mathematical expectation of sampling time t, EB is the mathematical expectation of bus current, Et 2 is the mathematical expectation of the square of the sampling time t, (Et) 2 is the square of the mathematical expectation of the sampling time t. Assume that Δt0 = t1-t0, Δt1 = t2-t1..., Δt k =t k+1 -t k In order to facilitate software calculation, it is generally designed as Δt0=Δt1=……=Δt k Therefore, the above formula can be simplified as follows: k=[B*∑(t*B)-∑t*∑B] / [B*∑t 2 -∑t*∑t], where B is a positive integer, Δt0, Δt1…Δt k is the time difference between two adjacent moments.

[0365] In some embodiments, the phase current of the motor 100 is an alternating current characteristic, and the motor 100 can be sampled by connecting current sensors to different output terminals of the motor 100, or the phase current can be obtained by connecting sampling resistors.

[0366] The phase current difference is: the phase current C obtained at the current moment is k Compared with the phase current C obtained at the previous moment k-1 Take the difference to get ΔCk The phase current difference can be an absolute value, that is, the obtained ΔC k is a positive number, which makes it easier to calculate the ratio later.

[0367] The slope of the phase current curve is: Get t0, t1, t2…t k Phase current C0, C1, C2...C k , C0, C1, C2…C k Perform linear fitting to obtain the corresponding curve slope k, whose formula (3) is: k=(EtC-Et*EC) / [Et 2 -(Et) 2 ] Where EtC is the mathematical expectation of the product of the sampling time t and the phase current, Et is the mathematical expectation of the sampling time t, EC is the mathematical expectation of the phase current, Et 2 is the mathematical expectation of the square of the sampling time t, (Et) 2 is the square of the mathematical expectation of the sampling time t. Assume that Δt0 = t1-t0, Δt1 = t2-t1..., Δt k =t k+1 -t k In order to facilitate software calculation, it is generally designed as Δt0=Δt1=……=Δt k Therefore, the above formula can be simplified as follows: k=[C*∑(t*C)-∑t*∑C] / [C*∑t 2 -∑t*∑t], where C is a positive integer, Δt0, Δt1, ..., Δt k is the time difference between two adjacent moments.

[0368] In some embodiments, the bus voltage of motor 100 may be a voltage between P+ and P-. The greater the load, the greater the relative voltage drop, and vice versa. In a battery-powered electric vehicle, the greater the load, the more significant the drop in battery pack terminal voltage. Since the terminal voltage corresponds to the bus voltage, the bus voltage can reflect the battery pack terminal voltage. The battery pack here may refer to the battery pack of the electric vehicle.

[0369] The bus voltage difference is: the bus voltage D obtained at the current moment is k The bus voltage D obtained at the previous moment k-1 Take the difference to get ΔD k The bus voltage difference can be an absolute value, that is, the obtained ΔD k is a positive number, which makes it easier to calculate the ratio later.

[0370] The slope of the bus voltage curve is: Get t0, t1, t2…t k Bus voltage D0, D1, D2...D at the moment k, D0, D1, D2…D k Perform linear fitting to obtain the corresponding curve slope k, whose formula (3) is: k=(EtD-Et*ED) / [Et 2 -(Et) 2 ] Where EtD is the mathematical expectation of the product of the sampling time t and the bus voltage, Et is the mathematical expectation of the sampling time t, ED is the mathematical expectation of the bus voltage, and Et 2 is the mathematical expectation of the square of the sampling time t, (Et) 2 is the square of the mathematical expectation of the sampling time t. Assume that Δt0 = t1-t0, Δt1 = t2-t1..., Δt k =t k+1 -t k In order to facilitate software calculation, it is generally designed as Δt0=Δt1=……=Δt k Therefore, the above formula can be simplified as follows: k=[D*∑(t*D)-∑t*∑D] / [D*∑t 2 -∑t*∑t], where D is a positive integer, * is the product of mathematical operations, Δt0, Δt1…Δt k is the time difference between two adjacent moments.

[0371] In some embodiments, the power is: P = U*I*p, where U is the bus voltage on the DC input side, I is the bus current, and p is the power factor, where p on the DC side is always equal to 1, or U is the phase voltage on the output side, I is the phase current, and p is the power factor, where p is less than or equal to 1.

[0372] The power difference and the slope of the power curve can refer to the above description of the difference and the slope, which will not be repeated below.

[0373] In some embodiments, the freewheeling time can be directly tested by a timer. The timer is started at each commutation to calculate the freewheeling time. The freewheeling time can represent the load size, where the larger the load, the longer the freewheeling time.

[0374] The freewheeling time difference and the slope of the freewheeling time curve can refer to the above description of the difference and the slope, which will not be repeated below.

[0375] In some embodiments, the duty cycle can be set according to actual conditions. The duty cycle can be tested by measuring the percentage of the time the circuit is turned on in the entire circuit working cycle. The larger the duty cycle, the higher the speed.

[0376] The duty cycle difference and the slope of the duty cycle curve can refer to the above description of the difference and the slope, which will not be repeated below.

[0377] In some embodiments, the ratio of different mechanical parameters to different electrical parameters can be the same type of ratios among the above parameters, such as the ratio between the rotational speed and the sector time, or the ratio between the rotational speed difference and the sector time difference, or the ratio between the rotational speed slope and the sector time slope, etc.

[0378] It is understandable that as the load increases, the speed decreases, the sector time increases, the torque decreases, the bus current increases, the phase current increases, the bus voltage decreases, the power increases, and the freewheeling time increases, and the duty cycle decreases. In other words, the speed and sector time are negatively correlated, the speed and torque are positively correlated, the sector time and torque are negatively correlated, the bus current and phase current are positively correlated, the bus current and bus voltage are negatively correlated, and the bus current and power are positively correlated. The negative correlation ratio will make the extraction of the ratio parameter more obvious and easier, and it can be easier to feedback whether the motor 100 is in a heavy load state, while the positive correlation ratio can simplify the calculation process of the detection module 101 and release the computing power of the detection module 101. The ratios of other different mechanical parameters and different electrical parameters can refer to the above description and will not be repeated below.

[0379] Referring to Figures 1 to 3, Figure 1 is a circuit diagram of an electric work vehicle provided in an embodiment of this specification; Figure 2 is a circuit diagram of a second electric work vehicle provided in an embodiment of this specification; and Figure 3 is a module diagram corresponding to an electric work vehicle provided in an embodiment of this specification.

[0380] 1 , the motor 100 may include a brushless motor, the acquisition module 104 may include: a back electromotive force acquisition module composed of a plurality of sampling resistors, and the judgment module 102 and the control module 103 may be integrated into a main control chip.

[0381] The electric work vehicle may further include a plurality of power devices MOSFET 105 .

[0382] Referring to FIG2 , when current parameters need to be collected, a current sampling module may be added. The current sampling module may include a sampling resistor and an operational amplifier.

[0383] Referring to Figures 5, 9 and 10, Figure 5 is the first flow chart provided in an embodiment of this specification, wherein open / closed-loop control is performed according to the current motor 100 control strategy of the entire machine, which means: according to the parameters of the obtained ratio, and selecting a control method other than the obtained parameters for control, taking the obtained ratio as the ratio between the speed and the sector time as an example, the motor 100 is controlled to be in the second operating state by controlling any parameter other than the speed and the sector time, for example, by controlling the torque of the motor 100 to be fixed to a certain parameter, or by controlling the power to be fixed to a certain parameter.

[0384] FIG9 is a graph obtained by sampling and drawing using current / speed as parameters, and FIG10 is a graph obtained by sampling and drawing using current / sector time as parameters. It can be seen from FIG9 and FIG10 that when the ratio suddenly changes to the target preset threshold, it is determined to be in an overload state.

[0385] In some embodiments, the determination module 102 further includes: comparing the ratio with a target preset threshold value, and determining that the motor 100 is in an overload state if the ratio does not meet the target preset threshold value.

[0386] Taking the rotation speed and sector time as an example, determine the current ratio (the ratio of the rotation speed to the sector time or the ratio of the sector time to the rotation speed) R k Is it less than or equal to (the ratio of the rotation speed to the sector time) or greater than or equal to (the ratio of the sector time to the rotation speed) a preset ratio threshold R T If so, it is determined that the load has entered the heavy load operation area.

[0387] Furthermore, a time restriction condition can be added. Within a preset ΔT time (for example, 0.01 to 10 seconds), the current ratio (the ratio of the rotational speed to the sector time or the ratio of the sector time to the rotational speed) R k Less than or equal to (ratio of rotation speed to sector time) or greater than or equal to (ratio of sector time to rotation speed) preset ratio threshold R T , it is determined that the load has entered the heavy load operation area.

[0388] Furthermore, the time limit added above can be segmented, with X ΔTs preset. x Time, for example, set X = 4, ΔT0 = 10 seconds, ΔT1 = 1 second, ΔT2 = 0.1 seconds, ΔT3 = 0.01 seconds, within ΔT0 (10 seconds) the current ratio (the ratio of the speed to the sector time or the ratio of the sector time to the speed) R k Less than or equal to (ratio of rotation speed to sector time) or greater than or equal to (ratio of sector time to rotation speed) preset ratio threshold R T0 , and / or the current ratio (ratio of rotational speed to sector time or ratio of sector time to rotational speed) R within ΔT1 (1 second) k Less than or equal to (ratio of rotation speed to sector time) or greater than or equal to (ratio of sector time to rotation speed) preset ratio threshold R T1 , and / or the current ratio (ratio of rotational speed to sector time or ratio of sector time to rotational speed) R within ΔT2 (0.1 seconds) k Less than or equal to (ratio of rotation speed to sector time) or greater than or equal to (ratio of sector time to rotation speed) preset ratio threshold R T2, and / or the current ratio (ratio of rotational speed to sector time or ratio of sector time to rotational speed) R within ΔT3 (0.01 seconds) k Less than or equal to (ratio of rotation speed to sector time) or greater than or equal to (ratio of sector time to rotation speed) preset ratio threshold R T3 , it is determined that the load has entered the heavy load operation area, R T0 ~R T3 Can satisfy R T0 ≥R T1 ≥R T2 ≥R T3 , or R T0 ≤R T1 ≤R T2 ≤R T3 .

[0389] It should be noted that the preset ratio here can be a range with an upper limit and a lower limit, and the preset ratio can also be greater than a certain value or less than a certain value as a basis for judgment. For example: if the ratio of different mechanical parameters obtained is greater than a certain value, the motor 100 can be regarded as being in an overloaded state; if the ratio of different mechanical parameters obtained is less than a certain value, the motor 100 can be regarded as being in an overloaded state.

[0390] Continuing to refer to Figure 5, in some embodiments, the motor 100 includes: a first gear, a second gear, and a third gear with increasing output capacity in sequence, and the target preset threshold is the same when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, or the target preset threshold decreases in sequence when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, or the target preset threshold increases in sequence when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear.

[0391] If the target preset threshold value is the same when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, for example, the target preset threshold value of the motor 100 in the first gear is 0.5-0.8, the target preset threshold value of the motor 100 in the second gear is 0.5-0.8, and the target preset threshold value of the motor 100 in the third gear is 0.5-0.8. Although the ratio value obtained when the motor 100 is in the first gear, the ratio value obtained when the motor 100 is in the second gear, and the ratio value obtained when the motor 100 is in the third gear may be different, the obtained ratio values ​​are all compared with the same target preset threshold value.

[0392] If the target preset threshold value decreases successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, that is, the target preset threshold value is the highest in the first gear and the lowest in the third gear, and the output capacity of the first gear is the weakest and the output capacity of the third gear is the strongest.

[0393] Refer to Table 1 below for an example. If the motor 100 is in the first gear, the target preset threshold is 0.5-0.8. If the motor 100 is in the second gear, the target preset threshold is 0.8-1.2. For example, when the motor 100 is in the third gear, the target preset threshold is 1.2-1.6. When determining the overload state, first determine which gear the motor 100 is in. Taking the ratio of 0.9 as an example, when the motor 100 is in the first gear, it is determined that the motor 100 is in the overload state. When the motor 100 is in the second gear, it is determined that the motor 100 is in the normal state. When the motor 100 is in the third gear, it is determined that the motor 100 is in the overload state.

[0394] Table 1

[0395] If the target preset threshold increases successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, that is, the target preset threshold is lowest in the first gear and highest in the third gear, and the output capacity of the first gear is the weakest and the output capacity of the third gear is the strongest, in other embodiments, the output capacity of the first gear may also be the strongest and the output capacity of the third gear may also be the weakest.

[0396] Refer to Table 2 below for an example. If the motor 100 is in the first gear, the target preset threshold is 1.2 to 1.6. If the motor 100 is in the second gear, the target preset threshold is 0.8 to 1.2. If the motor 100 is in the third gear, the target preset threshold is 0.5 to 0.8. When determining the overload state, first determine which gear the motor 100 is in. Taking the ratio of 0.9 as an example, when the motor 100 is in the first gear, it is determined that the motor 100 is in the overload state. When the motor 100 is in the second gear, it is determined that the motor 100 is in the normal state. When the motor 100 is in the third gear, it is determined that the motor 100 is in the overload state.

[0397] Table 2

[0398] It can be understood that setting the target preset threshold to be the same when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can reduce the complexity of the entire parameter setting and facilitate the judgment of the judgment module 102; setting the target preset threshold to decrease successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can be more in line with actual usage. For example, when the motor 100 is in the third gear, the output capacity of the motor 100 is the strongest, that is, the user does not want the motor 100 to stop running. Therefore, when the motor 100 is in the third gear, the target preset threshold can be set to the minimum, and it is more difficult to enter the overload state, thereby preventing the motor 100 from entering the second output state; setting the target preset threshold to increase successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can make the difficulty of judging the overload state in each gear the same.

[0399] It should be noted that the above description is for the situation where the ratio of different mechanical parameters or the ratio of different electrical parameters obtained decreases as the load increases. If the ratio of different mechanical parameters or the ratio of different electrical parameters obtained increases accordingly as the load increases, then setting the target preset threshold to decrease successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can make the difficulty of determining the heavy load state in each gear the same; setting the target preset threshold to increase successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can be more in line with actual usage.

[0400] Continuing to refer to Table 1 and Table 2, ΔT0 to ΔT4 are sampling time intervals that decrease in sequence, ΔT0 can be 10s, ΔT1 can be 1s, ΔT2 can be 0.1s, and ΔT3 can be 0.01s. In some embodiments, the target preset threshold is determined based on the sampling time, and the shorter the sampling time interval, the smaller the target preset threshold. The sampling time interval is: the time interval for obtaining two adjacent mechanical parameters or obtaining two adjacent electrical parameters. Taking the speed as an example, when the speed is relatively high, the speed sampling is far lower than the frequency of change of the actual speed, and the obtained data fluctuates greatly, or the actual speed change rate may have met the application requirements, but the actual calculation judgment fails to identify it. When the speed is relatively low, the speed sampling frequency is far higher than the frequency of the motor 100 speed filtering. The speed sampled at each moment may be the same, which wastes computing resources unnecessarily. Or when the speed of the motor 100 fluctuates on a small time scale, it is easy to interfere with the calculation result and form a misjudgment. Therefore, by setting the sampling time interval to be shorter, the target preset threshold is smaller, and the sampling time interval is longer, the target preset threshold is larger. On the one hand, it can reduce the consumed computing resources, and on the other hand, it can also improve the accuracy of identifying whether it has entered an overload state.

[0401] In this case, the target preset threshold here may refer to the difference between the target preset threshold and the target value. The shorter the sampling time interval, the smaller the difference, which can improve the accuracy of identifying whether entering the overload state.

[0402] Taking the ratio of sector time and rotational speed as an example, as the load increases, the ratio will increase. By setting the sampling time interval to be shorter and the target preset threshold to be smaller, the consumed computing resources can be reduced. On the other hand, it can also improve the accuracy of identifying whether it has entered an overload state. If taking the ratio of rotational speed and sector time as an example, as the load increases, the ratio will decrease. Then, the shorter the sampling time interval, the larger the target preset threshold should be set to improve the accuracy of identifying whether it has entered an overload state. In other words, the set target preset threshold is also related to the change of the target value. As the load increases, the target value increases, and the shorter the sampling time interval, the smaller the target preset threshold is set; as the load increases, the target value decreases, and the shorter the sampling time interval, the larger the target preset threshold is set.

[0403] It should be noted that the data in the above table are examples and represent the target preset threshold value. It can be understood that the data in the above table are examples and can also be other data and can also be values ​​in other ranges.

[0404] Refer to FIG6 , which is a second flow chart provided in an embodiment of this specification.

[0405] In some embodiments, the target calculation formula includes: calculating the ratio of different mechanical parameters of the motor 100, or the ratio of different electrical parameters of the motor 100, and calculating the ratio value of the ratio to the preset ratio, the target value is the ratio value, and the judgment module 102 also includes: comparing the ratio value with the target preset threshold value. If the ratio value does not meet the target preset threshold value, it is determined that the motor 100 is in an overloaded state.

[0406] It is understood that, taking the ratio of the rotational speed to the sector time as an example, the obtained ratio is the ratio of the current rotational speed to the current sector time, and the preset ratio is the ratio between the expected rotational speed and the expected sector time when the motor 100 is in a normal state. By comparing the ratio with the target preset threshold, the determination module 102 can also determine whether the motor 100 is in an overloaded state.

[0407] It should be noted that the preset ratio value here can be a range with an upper limit and a lower limit, and the preset ratio value can also be greater than a certain value or less than a certain value as a basis for judgment. For example: if the ratio of the obtained different mechanical parameters to the preset ratio is greater than a certain value, or the ratio of the obtained different electrical parameters to the preset ratio is greater than a certain value, then the motor 100 can be regarded as being in an overloaded state; similarly, if the ratio of the obtained different mechanical parameters to the preset ratio is less than a certain value, or the ratio of the obtained different electrical parameters to the preset ratio is less than a certain value, then the motor 100 can also be regarded as being in an overloaded state.

[0408] Continuing to refer to Figure 6, in some embodiments, the motor 100 includes: a first gear, a second gear, and a third gear with increasing output capacity in sequence, and the target preset threshold is the same when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, or the target preset threshold decreases in sequence when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, or the target preset threshold increases in sequence when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear.

[0409] If the target preset threshold value is the same when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, for example, the target preset threshold value of the motor 100 in the first gear is 40% to 60%, the target preset threshold value of the motor 100 in the second gear is 40% to 60%, and the target preset threshold value of the motor 100 in the third gear is 40% to 60%. Although the ratio value obtained when the motor 100 is in the first gear, the ratio value obtained when the motor 100 is in the second gear, and the ratio value obtained when the motor 100 is in the third gear may be different, the obtained ratio values ​​are all compared with the same target preset threshold value.

[0410] If the target preset threshold value decreases successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, that is, the target preset threshold value is the highest in the first gear and the lowest in the third gear, and the output capacity of the first gear is the weakest and the output capacity of the third gear is the strongest, in other embodiments, the output capacity of the first gear may also be the strongest and the output capacity of the third gear may also be the weakest.

[0411] Refer to Table 3 below for an example. If the motor 100 is in the first gear, the target preset threshold is 30% to 50%. If the motor 100 is in the second gear, the target preset threshold is 50% to 70%. For example, when the motor 100 is in the third gear, the target preset threshold is 70% to 90%. When determining the overload state, first determine which gear the motor 100 is in. Taking the ratio value of 55% as an example, when the motor 100 is in the first gear, it is determined that the motor 100 is in the overload state. When the motor 100 is in the second gear, it is determined that the motor 100 is in the normal state. When the motor 100 is in the third gear, it is determined that the motor 100 is in the overload state.

[0412] Table 3

[0413] If the target preset threshold increases successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, that is, the target preset threshold is lowest in the first gear and highest in the third gear, the output capacity of the first gear is the weakest and the output capacity of the third gear is the strongest.

[0414] Refer to Table 4 below for an example. If the motor 100 is in the first gear, the target preset threshold is 70% to 90%. If the motor 100 is in the second gear, the target preset threshold is 50% to 70%. For example, when the motor 100 is in the third gear, the target preset threshold is 30% to 50%. When determining the overload state, first determine which gear the motor 100 is in. Taking the ratio value of 55% as an example, when the motor 100 is in the first gear, it is determined that the motor 100 is in the overload state. When the motor 100 is in the second gear, it is determined that the motor 100 is in the normal state. When the motor 100 is in the third gear, it is determined that the motor 100 is in the overload state.

[0415] Table 4

[0416] It can be understood that setting the target preset threshold to be the same when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can reduce the complexity of the entire parameter setting and facilitate the judgment of the judgment module 102; setting the target preset threshold to decrease successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can be more in line with actual usage. For example, when the motor 100 is in the third gear, the output capacity of the motor 100 is the strongest, that is, the user does not want the motor 100 to stop running. Therefore, when the motor 100 is in the third gear, the target preset threshold can be set to the minimum, and it is more difficult to enter the overload state, thereby preventing the motor 100 from entering the second output state; setting the target preset threshold to increase successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can make the difficulty of judging the overload state in each gear the same.

[0417] It should be noted that the above description is for the case where, as the load increases, the ratio of the ratio of different mechanical parameters obtained to the preset ratio decreases, or the ratio of different electrical parameters obtained to the preset ratio decreases. If, as the load increases, the ratio of the ratio of different mechanical parameters obtained to the preset ratio increases accordingly, or the ratio of different electrical parameters obtained to the preset ratio increases accordingly, then setting the target preset threshold to decrease successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can make the difficulty of determining the heavy load state in each gear the same; setting the target preset threshold to increase successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can be more in line with actual usage.

[0418] Continuing to refer to Table 3 and Table 4, ΔT0 to ΔT4 are sampling time intervals that decrease in sequence, ΔT0 can be 10s, ΔT1 can be 1s, ΔT2 can be 0.1s, and ΔT3 can be 0.01s. In some embodiments, the target preset threshold is determined according to the sampling time, and the shorter the sampling time interval, the smaller the target preset threshold. The sampling time interval is: the time interval for obtaining two adjacent mechanical parameters or obtaining two adjacent electrical parameters. Taking the speed as an example, when the speed is relatively high, the speed sampling is far lower than the frequency of change of the actual speed, and the obtained data fluctuates greatly, or the actual speed change rate may have met the application requirements, but the actual calculation judgment fails to identify it. When the speed is relatively low, the speed sampling frequency is far higher than the frequency of the motor 100 speed filtering. The speed sampled at each moment may be the same, which wastes computing resources unnecessarily. Or when the speed of the motor 100 fluctuates on a small time scale, it is easy to interfere with the calculation result and form a misjudgment. Therefore, by setting the sampling time interval to be shorter, the target preset threshold is smaller, and the sampling time interval is longer, the target preset threshold is larger. On the one hand, it can reduce the consumed computing resources, and on the other hand, it can also improve the accuracy of identifying whether it has entered an overload state.

[0419] It should be noted that the data in the above table are also examples and represent the target preset threshold value. It can be understood that the data in the above table are examples and can also be other data and can also be values ​​in other ranges.

[0420] Referring to Figures 7, 11, and 12, Figure 7 is a third flow chart provided in one embodiment of this specification. Figure 11 is a graph plotted using the difference between current and speed as a sampling parameter, and Figure 12 is a graph plotted using the difference between current and sector time as a sampling parameter. As can be seen from Figures 11 and 12, a heavy load state is determined when the ratio suddenly reaches a target preset threshold.

[0421] In some embodiments, the target calculation formula includes calculating a ratio of different mechanical parameters of the motor 100 or a ratio of different electrical parameters of the motor 100, and calculating a difference between the ratios within a preset time, wherein the target value is the difference. The determination module 102 further includes comparing the difference with a preset target threshold value, and determining that the motor 100 is in an overloaded state if the difference does not meet the preset target threshold value. Comparing the difference with the preset target threshold value also facilitates the determination module 102 in determining whether the motor 100 is in an overloaded state.

[0422] Similarly, the difference between the speed and sector time and the ratio of sector time to speed are used as examples for explanation (the ideas and methods for the difference between the ratios of other different mechanical parameters or different electrical parameters are the same as those for the difference between the speed and sector time).

[0423] The ratio obtained at the current moment (the ratio of the speed to the sector time or the ratio of the sector time to the speed) R k Ratio R obtained at the previous moment k-1 Take the difference to get ΔR k , if ΔR k Greater than or equal to the target preset threshold ΔR T , it is determined that the load has entered the heavy load operation area.

[0424] Furthermore, a time constraint condition can be added. Within a preset ΔT time (eg, 0.01 to 10 seconds), the current ratio difference ΔR k Greater than or equal to the target preset threshold ΔR T , it is determined that the load has entered the heavy load operation area.

[0425] Furthermore, the time limit added above can be segmented, with X ΔTs preset. x Time, for example, set X = 4, ΔT0 = 10 seconds, ΔT1 = 1 second, ΔT2 = 0.1 seconds, ΔT3 = 0.01 seconds, and the ratio R obtained at the current moment k Ratio R to the previous ΔT0 (10 seconds) g Take the difference to get ΔR kg , R k Ratio R to the previous ΔT1 (1 second) h Take the difference to get ΔR kh , R k Ratio R to the previous ΔT2 (0.1 second) i Take the difference to get ΔR ki , R k Ratio R to the previous ΔT3 (0.01 seconds) j Take the difference to get ΔR kj , if ΔR kg Greater than or equal to the target preset threshold ΔR T0 , and / or ΔR kh Greater than or equal to the target preset threshold ΔR T1 , and / or ΔR ki Greater than or equal to the target preset threshold ΔR T2 , and / or ΔR kj Greater than or equal to the target preset threshold ΔR T3 , it is determined that the load has entered the heavy load operation area, ΔR T0 ~ΔR T3 Can satisfy ΔR T0 ≥ΔR T1 ≥ΔR T2 ≥ΔR T3 , or, ΔR T0 ≤ΔR T1 ≤ΔRT2 ≤ΔR T3 .

[0426] Continuing to refer to Figure 7, in some embodiments, the motor 100 includes: a first gear, a second gear, and a third gear with increasing output capacity in sequence, and the target preset threshold is the same when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, or the target preset threshold decreases in sequence when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, or the target preset threshold increases in sequence when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear.

[0427] If the target preset threshold value is the same when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, for example, the target preset threshold value of the motor 100 in the first gear is 0.1-0.3, the target preset threshold value of the motor 100 in the second gear is 0.1-0.3, and the target preset threshold value of the motor 100 in the third gear is 0.1-0.3. The difference value obtained when the motor 100 is in the first gear, the difference value obtained when the motor 100 is in the second gear, and the difference value obtained when the motor 100 is in the third gear may be different, but the obtained difference values ​​are all compared with the same target preset threshold value.

[0428] If the target preset threshold value decreases successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, that is, the target preset threshold value is the highest in the first gear and the lowest in the third gear, and the output capacity of the first gear is the weakest and the output capacity of the third gear is the strongest.

[0429] Refer to Table 5 below for an example. If the motor 100 is in the first gear, the target preset threshold is 0.1-0.3. If the motor 100 is in the second gear, the target preset threshold is 0.3-0.5. For example, when the motor 100 is in the third gear, the target preset threshold is 0.5-0.7. When determining whether the motor 100 is in an overloaded state, first determine which gear the motor 100 is in. Taking the difference of 0.4 as an example, when the motor 100 is in the first gear, it is determined that the motor 100 is in an overloaded state. When the motor 100 is in the second gear, it is determined that the motor 100 is in a normal state. When the motor 100 is in the third gear, it is determined that the motor 100 is in an overloaded state.

[0430] Table 5

[0431] If the target preset threshold increases successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, that is, the target preset threshold is lowest in the first gear and highest in the third gear, the output capacity of the first gear is the weakest and the output capacity of the third gear is the strongest.

[0432] Refer to Table 6 below for an example. If the motor 100 is in the first gear, the target preset threshold is 0.5-0.7. If the motor 100 is in the second gear, the target preset threshold is 0.3-0.5. For example, when the motor 100 is in the third gear, the target preset threshold is 0.1-0.3. When determining the overload state, first determine which gear the motor 100 is in. Taking the difference of 0.4 as an example, when the motor 100 is in the first gear, it is determined that the motor 100 is in the overload state. When the motor 100 is in the second gear, it is determined that the motor 100 is in the normal state. When the motor 100 is in the third gear, it is determined that the motor 100 is in the overload state.

[0433] Table 6

[0434] It can be understood that setting the target preset threshold to be the same when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can reduce the complexity of the entire parameter setting and facilitate the judgment of the judgment module 102; setting the target preset threshold to decrease in sequence when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can be more in line with actual usage. For example, when the motor 100 is in the third gear, the output capacity of the motor 100 is the strongest, that is, the user does not want the motor 100 to It will stop running, so the target preset threshold can be set to be the smallest when the motor 100 is in the third gear, making it more difficult to enter the overload state, thereby preventing the motor 100 from entering the second output state; the target preset threshold is set to increase successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, so that the difficulty of determining the overload state in each gear is the same. The difficulty here refers to the judgment standard for determining whether the motor 100 enters the overload state. In other words, the amplitude of change in the first gear, the second gear, and the third gear are the same, and the degree of change is the same.

[0435] It should be noted that the above description is for the case where the ratio of different mechanical parameters obtained decreases as the load increases, or the ratio of different electrical parameters obtained decreases. If the ratio of different mechanical parameters obtained increases accordingly as the load increases, or the ratio of different electrical parameters obtained increases, then setting the target preset threshold to decrease successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can make the difficulty of determining the heavy load state in each gear the same; setting the target preset threshold to increase successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can be more in line with actual usage.

[0436] Continuing to refer to Table 5 and Table 6, ΔT0 to ΔT4 are sampling time intervals that decrease in sequence, ΔT0 can be 10s, ΔT1 can be 1s, ΔT2 can be 0.1s, and ΔT3 can be 0.01s. In some embodiments, the target preset threshold is determined according to the sampling time, and the shorter the sampling time interval, the smaller the target preset threshold. The sampling time interval is: the time interval for obtaining two adjacent mechanical parameters or obtaining two adjacent electrical parameters. Taking the speed as an example, when the speed is relatively high, the speed sampling is far lower than the frequency of change of the actual speed, and the obtained data fluctuates greatly, or the actual speed change rate may have met the application requirements, but the actual calculation judgment fails to identify it. When the speed is relatively low, the speed sampling frequency is far higher than the frequency of the motor 100 speed filtering. The speed sampled at each moment may be the same, which wastes computing resources unnecessarily. Or when the speed of the motor 100 fluctuates on a small time scale, it is easy to interfere with the calculation result and form a misjudgment. Therefore, by setting the sampling time interval to be shorter, the target preset threshold is smaller, and the sampling time interval is longer, the target preset threshold is larger. On the one hand, it can reduce the consumed computing resources, and on the other hand, it can also improve the accuracy of identifying whether it has entered an overload state.

[0437] It should be noted that the data in the above table are also examples and represent the target preset threshold value. It can be understood that the data in the above table are examples and can also be other data and can also be values ​​in other ranges.

[0438] Referring to Figures 8, 13 and 14, Figure 8 is a fourth flow chart provided in an embodiment of this specification, Figure 13 is a curve diagram of the slope sampled and drawn with current / speed as parameters, and Figure 14 is a curve diagram of the slope sampled and drawn with current / sector time as parameters. It can be seen from Figures 13 and 14 that when the slope of the ratio curve suddenly changes to the target preset threshold, it is determined to be an overload state.

[0439] In some embodiments, the target calculation formula includes: calculating the ratio of different mechanical parameters of the motor 100, or the ratio of different electrical parameters of the motor 100, and calculating the slope of the ratio, the target value is the slope, and the judgment module 102 also includes: comparing the slope with the target preset threshold, if the slope does not meet the target preset threshold, determining that the motor 100 is in an overloaded state.

[0440] Take the slope of the curve of the ratio of speed to sector time and sector time to speed as an example (the idea and method of the slope of the ratio of other mechanical parameters or different electrical parameters are the same as the idea and method of the slope of the ratio of speed to sector time). Get t0, t1, t2…t k The ratio of the time R0, R1, R2...R k , R0, R1, R2…Rk Perform linear fitting to obtain the corresponding curve slope k, which is expressed in formula (15): k = (Eti–Et*Ei) / [Et 2 –(Et) 2 ]. In the formula, Etr is the mathematical expectation of the product of the sampling time t and the ratio, Et is the mathematical expectation of the sampling time t, Er is the mathematical expectation of the ratio, Et 2 is the mathematical expectation of the square of the sampling time t, (Et) 2 is the square of the mathematical expectation of the sampling time t, assuming that Δt0 = t1-t0, Δt1 = t2-t1..., Δt k =t k+1 -t k In order to facilitate software calculation, it is generally designed as Δt0=Δt1=……=Δt k Therefore, the above formula can be simplified to: k = [n*Σ(t*r)-Σt*Σr] / [n*Σt 2 -Σt*Σt], where n is a positive integer. In order to further simplify the calculation process and reduce software calculation overhead, n in the above simplified formula can be set to 2 m , m is a positive integer. When m=1, the above formula degenerates into the difference of the above ratios. When the slope k is greater than or equal to the ratio of (sector time to speed) the slope threshold k is set. T , or less than or equal to the preset slope threshold k (ratio of rotation speed to sector time) T , which means that the load is determined to have entered the heavy load operation area.

[0441] Continuing to refer to Figure 8, in some embodiments, the motor 100 includes: a first gear, a second gear, and a third gear with increasing output capacity in sequence, and the target preset threshold is the same when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, or the target preset threshold decreases in sequence when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, or the target preset threshold increases in sequence when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear.

[0442] If the target preset threshold is the same when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, for example, the target preset threshold when the motor 100 is in the first gear is 1 to 3, the target preset threshold when the motor 100 is in the second gear is 1 to 3, and the target preset threshold when the motor 100 is in the third gear is 1 to 3. The difference value obtained when the motor 100 is in the first gear, the difference value obtained when the motor 100 is in the second gear, and the difference value obtained when the motor 100 is in the third gear may be different, but the obtained difference values ​​are all compared with the same target preset threshold.

[0443] If the target preset threshold value decreases successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, that is, the target preset threshold value is the highest in the first gear and the lowest in the third gear, and the output capacity of the first gear is the weakest and the output capacity of the third gear is the strongest.

[0444] Refer to Table 7 below for an example. If the motor 100 is in the first gear, the target preset threshold is 1 to 3. If the motor 100 is in the second gear, the target preset threshold is 3 to 5. For example, when the motor 100 is in the third gear, the target preset threshold is 5 to 7. When determining whether the motor 100 is in an overloaded state, first determine which gear the motor 100 is in. Taking the difference case of 4 as an example, when the motor 100 is in the first gear, it is determined that the motor 100 is in an overloaded state. When the motor 100 is in the second gear, it is determined that the motor 100 is in a normal state. When the motor 100 is in the third gear, it is determined that the motor 100 is in an overloaded state.

[0445] Table 7

[0446] If the target preset threshold increases successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, that is, the target preset threshold is lowest in the first gear and highest in the third gear, the output capacity of the first gear is the weakest and the output capacity of the third gear is the strongest.

[0447] Refer to Table 8 below for an example. If the motor 100 is in the first gear, the target preset threshold is 5 to 7. If the motor 100 is in the second gear, the target preset threshold is 3 to 5. For example, when the motor 100 is in the third gear, the target preset threshold is 1 to 3. When determining the overload state, first determine which gear the motor 100 is in. Taking the difference case of 4 as an example, when the motor 100 is in the first gear, it is determined that the motor 100 is in the overload state. When the motor 100 is in the second gear, it is determined that the motor 100 is in the normal state. When the motor 100 is in the third gear, it is determined that the motor 100 is in the overload state.

[0448] Table 8

[0449] It can be understood that setting the target preset threshold to be the same when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can reduce the complexity of the entire parameter setting and facilitate the judgment of the judgment module 102; setting the target preset threshold to decrease in sequence when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can be more in line with actual usage. For example, when the motor 100 is in the third gear, the output capacity of the motor 100 is the strongest, that is, the user does not want the motor 100 to It will stop running, so the target preset threshold can be set to be the smallest when the motor 100 is in the third gear, making it more difficult to enter the overload state, thereby preventing the motor 100 from entering the second output state; the target preset threshold is set to increase successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear, so that the difficulty of determining the overload state in each gear is the same. The difficulty here refers to the judgment standard for determining whether the motor 100 enters the overload state. In other words, the amplitude of change in the first gear, the second gear, and the third gear are the same, and the degree of change is the same.

[0450] It should be noted that the above description is for the situation where the ratio of the obtained mechanical parameters and electrical parameters decreases as the load increases. If the ratio of the obtained mechanical parameters and electrical parameters increases accordingly as the load increases, then setting the target preset threshold to decrease successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can make the difficulty of determining the heavy load state in each gear the same; setting the target preset threshold to increase successively when the motor 100 is in the first gear, the motor 100 is in the second gear, and the motor 100 is in the third gear can be more in line with actual usage.

[0451] Continuing to refer to Tables 7 and 8, ΔT0 to ΔT4 are sampling time intervals that decrease in sequence, ΔT0 may be 10s, ΔT1 may be 1s, ΔT2 may be 0.1s, and ΔT3 may be 0.01s. In some embodiments, the target preset threshold value may be determined based on the sampling time, and the shorter the sampling time interval, the smaller the target preset threshold value. The sampling time interval is: the time interval for obtaining two adjacent mechanical parameters or obtaining two adjacent electrical parameters. Taking the speed as an example, when the speed is relatively high, the speed sampling is far lower than the frequency of change of the actual speed, and the obtained data fluctuates greatly, or the actual speed change rate may have met the application requirements, but the actual calculation judgment fails to identify it. When the speed is relatively low, the speed sampling frequency is far higher than the frequency of the motor 100 speed filtering. The speed sampled at each moment may be the same, which wastes computing resources unnecessarily. Or when the speed of the motor 100 fluctuates on a small time scale, it is easy to interfere with the calculation result and form a misjudgment. Therefore, by setting the sampling time interval to be shorter, the target preset threshold is smaller, and the sampling time interval is longer, the target preset threshold is larger. On the one hand, it can reduce the consumed computing resources, and on the other hand, it can also improve the accuracy of identifying whether it has entered an overload state.

[0452] It should be noted that the data in the above table are also examples and represent the target preset threshold value. It can be understood that the data in the above table are examples and can also be other data and can also be values ​​in other ranges.

[0453] In some embodiments, before obtaining the slopes of the ratios of different mechanical parameters or the slopes of the ratios of different electrical parameters, the determination module 102 further includes: filtering the obtained ratios of different mechanical parameters or the obtained ratios of different electrical parameters.

[0454] In some embodiments, the filtering methods mainly include: fixed window filtering, sliding window filtering, arithmetic mean filtering, de-extreme value average filtering, median filtering, etc. Different algorithms can be combined, such as fixed window arithmetic mean filtering, sliding window median filtering, etc., so that the above ratios R0, R1, R2...R k is the value obtained after filtering. When the fixed window filter series method is used, Δt0, Δt1, Δt2…Δt k The value is X ratio sampling intervals. For example, when the ratio is obtained every 1ms, and X is preset to 8, the filtered value will be calculated every 8ms, Δt0 = Δt1 = Δt2 = Δt k =8ms; When the sliding window filter series method is used, the above preset conditions are still applied, then Δt0=Δt1=Δt2=Δt k=1ms. After each fixed window filtering or sliding window filtering is completed, the slope k is calculated using the above method for obtaining the slope of the ratio, which is the first-order derivative value of the ratio with respect to unit time.

[0455] It can be understood that the fixed window filtering method is: obtain a ratio every Xms, and obtain a total of n values. For example, obtain a ratio every 1ms, and obtain a total of 8 ratios. Each time the ratio is obtained, it is a group of 8 ratios. The sliding window filtering method is: obtain a ratio every Xms, and obtain a total of n ratios, but the next group of ratios is the last n-1 of the previous group of ratios and the newly obtained ratio is the next group of ratios. For example, obtain a ratio every 1ms, and obtain a total of 8 ratios. The ratio obtained in the next 1ms and the last 7 ratios in the previous group of ratios constitute a new group of resistance values. The arithmetic average filtering method is: obtain the arithmetic mean of each group of ratios; the extreme value average filtering method is: after obtaining each group of ratios, remove the n maximum values ​​and n minimum values; the median filtering method is: after obtaining each group of ratios, take the median of each group of ratios.

[0456] Furthermore, if the ratio span of the motor 100 is relatively large, Δt0, Δt1, Δt2, ... Δt k The value of can be adjusted dynamically according to the current motor 100 ratio, because if Δt0, Δt1, Δt2…Δt k If it is too small, when the motor 100 ratio is relatively low, the ratio sampling frequency is much higher than the motor 100 ratio filtering frequency, and the ratio sampled at each moment may be the same, which wastes computing resources unnecessarily. Or, when the motor 100 ratio fluctuates on a small time scale, it is easy to interfere with the calculation result and form a misjudgment. If Δt0, Δt1, Δt2…Δt k If it is too large, when the ratio of the motor 100 is relatively high, the ratio sampling is far lower than the actual ratio change frequency, and the obtained data fluctuates greatly, or the actual ratio change rate may have met the application requirements, but the actual calculation judgment fails to recognize it. Therefore, Δt0, Δt1, Δt2…Δt k The adjustment rule is that when the ratio is high, the time interval is small, and when the ratio is low, the time interval is large. There are three ways to adjust this time interval. The first is to adjust the above 1ms ratio sampling interval, for example, to 0.5ms or 2ms. In this way, under the fixed window filter series method, Δt0 = Δt1 = Δt2 = Δt k =4ms or 16ms, under the sliding window filter series method, Δt0=Δt1=Δt2=Δt k=0.5ms or 2ms; the second is to adjust the window length (number of sampling points X), for example, to X=4 or X=16, so that under the fixed window filter series method Δt0=Δt1=Δt2=Δt k =4ms or 16ms, under the sliding window filter series method, Δt0=Δt1=Δt2=Δt k Still equal to 1ms; the third method is to adjust the ratio sampling interval and the window length (number of sampling points X) at the same time. In addition, since the ratio decreases rapidly when the load suddenly changes, this process will not adjust Δt0, Δt1, Δt2...Δt k , and adjustments will only be made after the ratio has stabilized for a period of time.

[0457] Furthermore, after each fixed window filtering or sliding window filtering, the slope is obtained using the above-mentioned slope obtaining method, so that a set of k0, k1, k2...k k , for k0, k1, k2…k k Then perform linear fitting to obtain the corresponding slope k', the formula is: k'=(Etk-Et*Ek) / [Et 2 -(Et) 2 ]. Where: Etk is the mathematical expectation of the ratio slope and the time t at which the ratio slope is obtained each time, Et is the mathematical expectation of the time t at which the ratio slope is obtained each time, Ek is the mathematical expectation of the ratio slope, Et 2 is the mathematical expectation of the square of the time t at which the slope of the ratio is obtained each time, (Et) 2 is the square of the mathematical expectation at sampling time t.

[0458] Since k0, k1, k2…k are obtained each time k The time intervals are equal, so Δt'0, Δt'1, Δt'2…Δt' k Therefore, the above formula can be simplified to: k'=[n'*Σ(t*k)-Σt*Σk] / [n'*Σt 2 -Σt*Σt], where n' is a positive integer. In order to further simplify the calculation process and reduce software calculation overhead, n' in the above simplified formula can be set to 2 m’ , m' is a positive integer. When the slope k' is greater than or equal to (the ratio of current to speed) or less than or equal to (the ratio of speed to current) the preset slope threshold k' T , which means the load has entered the heavy load operation area. Here, the slope k' is the second-order derivative of the ratio with respect to unit time.

[0459] It should be noted that the above descriptions are all based on two mechanical parameters or two electrical parameters of the motor as examples. In fact, multiple mechanical parameters or multiple electrical parameters of the motor can also be collected through the acquisition module, and the detection module can also compare multiple mechanical parameters or multiple electrical parameters.

[0460] 1 and 2 , in some embodiments, the electric work vehicle may further include: a control module 103, which is configured to adjust the mechanical or electrical parameters of the motor 100 when the motor 100 is in an overloaded state to reduce the working efficiency of the motor 100 until the motor 100 is out of the overloaded state. The control module 103 can control the mechanical or electrical parameters of the motor 100, thereby preventing the motor 100 from stopping and also preventing damage to components in the electric work vehicle, thereby improving user comfort and reliability of the electric work vehicle. For example, when the control module 103 controls the speed of the motor 100, when the judgment module 102 determines that the motor 100 is in an overloaded state, the speed of the motor 100 is reduced to prevent the motor 100 from continuing to operate at the initial speed, thereby preventing damage to components in the electric work vehicle.

[0461] It should be noted that the working efficiency here may refer to the mowing capacity of the electric work vehicle, and the mowing capacity refers to the weight of grass that can be cut per unit time, or the area of ​​lawn that can be mowed per unit time, etc.

[0462] In some embodiments, the control module 103 may be integrated into the same chip as the detection module 101 and the judgment module 102 .

[0463] In some embodiments, the control module 103 adjusts the mechanical parameters or electrical parameters of the motor 100 to be different from the mechanical parameters and electrical parameters collected by the acquisition module 104 to avoid mutual interference between the control module 103 and the acquisition module 104 .

[0464] In the embodiment of this specification, the acquisition module 104 acquires the mechanical parameters or electrical parameters of the motor, which can facilitate the detection module 101 to generate a target value. The detection module 101 processes different mechanical parameters or different electrical parameters of the motor 100 according to the target calculation formula to obtain the target value, thereby facilitating the judgment module 102 to judge whether the motor 100 is in an overloaded state. The ratio of different mechanical parameters or different electrical parameters can, on the one hand, more easily provide feedback on whether the motor 100 is in an overloaded state, and on the other hand, simplify the calculation of the entire ratio, thereby releasing the computing power of the detection module 101 and providing a more accurate judgment of whether the motor 100 is in an overloaded state through the ratio of mechanical parameters to electrical parameters.

[0465] Another embodiment of the present specification also provides a method for detecting a heavy-load state, which can be implemented by the electric work vehicle of all or part of the above embodiments. The method for detecting a heavy-load state provided by another embodiment of the present specification will be described below. It should be noted that for the same or corresponding parts as the above embodiments, reference can be made to the corresponding descriptions of the above embodiments, and will not be repeated below.

[0466] In some embodiments, the method for detecting a heavy load state provided in the embodiments of this specification may include: collecting at least two mechanical parameters or at least two electrical parameters of the motor, the mechanical parameters including speed parameters, sector time parameters or torque parameters, and the electrical parameters including bus current parameters, phase current parameters, bus voltage parameters, power parameters, freewheeling time parameters or duty cycle parameters.

[0467] The method for detecting a heavy load state provided in the embodiments of this specification may further include: processing different mechanical parameters of the motor according to a target calculation formula, or processing different electrical parameters of the motor, and generating a target value, wherein the target calculation formula includes at least a ratio, a slope of a ratio, or a difference in a ratio, etc.

[0468] The overload state detection method provided in the embodiment of this specification may also include: determining whether the motor is in an overload state based on a target value and a target preset threshold value; if the target value does not meet the target preset threshold value, determining that the motor is in an overload state, wherein the target preset threshold value corresponds to a target calculation formula.

[0469] The embodiments of this specification collect different mechanical parameters or electrical parameters of the motor to generate target values, and process the mechanical parameters or electrical parameters of the motor according to the target calculation formula to obtain the target values, so as to facilitate the judgment of whether the motor is in an overloaded state. The ratio of the mechanical parameters or electrical parameters can, on the one hand, more easily provide feedback on whether the motor is in an overloaded state, and on the other hand, simplify the calculation of the entire ratio, and provide a more accurate judgment of whether the motor is in an overloaded state through the ratio of the mechanical parameters or electrical parameters.

[0470] Based on the same purpose, in another aspect, an embodiment of this specification provides an electric work vehicle.

[0471] As shown in Figures 15 to 17, one or more optional embodiments of this specification provide an electric work vehicle, including:

[0472] The vehicle frame 200 is connected to the functional mechanism 21 and the driving mechanism 23 of the vehicle frame.

[0473] The frame 200 extends at least partially in parallel with the front-to-back direction, and a carrying mechanism 201 may be provided on the frame 200. The carrying mechanism 201 is used to carry the operator of the electric work vehicle, and may include at least one of a seat or a standing platform. FIG15 only exemplarily shows the case where the carrying mechanism 201 includes a seat. The seat or the standing platform is used for sitting or standing during work. That is, the electric work vehicle can provide a riding working mode or a standing working mode. Furthermore, the structure of the seat and the standing platform can be flexibly switched, that is, the working mode of the electric work vehicle can be flexibly switched between a riding working mode and a standing working mode according to the actual needs of the working user. A handheld operating component may also be provided on the frame 200. Based on the handheld operating component, the electric work vehicle can also provide a hand-pushing working mode.

[0474] The functional mechanism 21 is attached to the vehicle frame 200 and includes a functional motor 211 and an output assembly driven by the functional motor 211 to perform a specific functional operation. It is understood that the functional mechanism 21 may include multiple output assemblies, and the multiple output assemblies are driven by at least one functional motor 21.

[0475] The drive mechanism 23 is used to enable the electric working vehicle to travel in a landscape setting, such as a lawn, garden, fence, green, or other surface, and includes a drive motor and drive wheels driven by the drive motor. During the operation of the electric working vehicle, the functional mechanism 21 performs corresponding functional operations in an orderly manner under the control of the controller assembly 22.

[0476] As shown in FIG. 15 , the electric working vehicle further includes a power supply system 24 , which is used to supply power to the functional mechanism 21 and the driving mechanism 23 .

[0477] The power system 24 is mounted on the vehicle frame 200 and is detachably connected thereto. The power system 24 includes a plurality of battery cells. The plurality of battery cells may be selected from at least one of a first specification battery pack and a second specification battery pack. Specification differences between the first specification battery pack and the second specification battery pack include, but are not limited to, differences in battery pack capacity, voltage, internal resistance, weight, size, energy density, cell type, charge information, and battery health status information.

[0478] In some optional embodiments, the difference between the first specification battery pack and the second specification battery pack is the different battery pack capacities. The capacity of the first specification battery pack is greater than the capacity of the second specification battery pack. The second specification battery pack is configured to provide power for handheld garden tools. For example, the second specification battery pack can power garden tools such as lawn mowers, pruners, hair dryers, and chainsaws. In addition, the second specification battery pack can also power torque output tools such as electric drills and electric hammers; power sawing tools such as electric circular saws, jigsaws, and reciprocating saws, or power grinding tools such as angle grinders and sanders.

[0479] In some optional embodiments, the difference between the first and second battery packs lies in the type of battery cells used. For example, the first and second battery packs may use lithium iron phosphate cells and ternary lithium cells, respectively. The multiple battery cells in the power supply system may also use nickel-cadmium battery cells, lead-acid battery cells, graphene battery cells, etc.

[0480] The multiple battery cells of the power supply system 24 select at least one of the first specification battery pack and the second specification battery pack. This makes the electric work vehicle compatible with battery packs of different specifications, meeting high-power working requirements while also being adaptable to handheld electric garden tools, making the working methods of the staff more flexible.

[0481] In some optional embodiments, the functional mechanism 21 is configured to perform a mowing function. The functional mechanism 21 includes a mowing motor 213 and a mowing element driven by the mowing motor 213. The functional mechanism 21 may include one or more mowing elements, each of which is driven by at least one mowing motor 213.

[0482] It can be understood that in some optional embodiments, the output component in the functional mechanism 21 can also be replaced with other functional components, such as snow sweeping, snow blowing, snow shoveling, flushing and other components. Those skilled in the art should be able to adaptively replace various functional components without creative work, and the above should all be included in the scope of protection of this embodiment.

[0483] In the electric work vehicle, a controller assembly 22 is provided corresponding to the functional mechanism 21. The controller assembly 22 is used to control the operating status of the functional motor 211. As shown in FIG16 , the controller assembly 22 can be provided in an integrated controller system of the electric work vehicle or independently. The control chip used in the controller assembly 22 can be, for example, a microcontroller (MCU), an advanced RISC machine (ARM), or the like.

[0484] The functional motor 211 has a variety of operating parameters. When the controller component 22 controls the functional motor 211 , a variety of control strategies corresponding to the various operating parameters can be selected.

[0485] The various operating parameters of the functional motor 211 may include, for example, speed parameters, electrical parameters, power parameters, torque parameters, and PWM duty cycle parameters.

[0486] The controller component 22 may select various control strategies corresponding to the above-mentioned operating parameters, including speed closed-loop control strategy, current closed-loop control strategy, power closed-loop control strategy, torque closed-loop control strategy and PWM duty cycle open-loop control strategy.

[0487] As shown in FIG. 17 , in some optional embodiments, the controller component 22 includes a heavy load identification unit 221 and a heavy load control unit 222 .

[0488] The overload identification unit 221 is configured to select a target operating parameter from the multiple operating parameters for monitoring, and determine whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter.

[0489] The target operating parameter does not match the first control strategy currently implemented by the controller component 22 for the functional motor 211. For example, if the first control strategy currently implemented by the controller component 22 is the speed closed-loop control strategy, an operating parameter other than the speed parameter is selected as the target operating parameter. Alternatively, if the first control strategy currently implemented by the controller component 22 is not the torque closed-loop control strategy, the torque parameter can be selected as the target operating parameter.

[0490] It is understandable that there are multiple operating parameters that do not match the current first control strategy, and the overload identification unit 221 can select one or more operating parameters as the target operating parameters for monitoring.

[0491] When the functional motor 211 experiences a sudden overload during operation, the load torque suddenly increases, and the corresponding motor speed, motor power, duty cycle, and related electrical parameters will fluctuate accordingly. The heavy load identification unit 221 monitors one or more operating parameters related to the functional motor 211, and can accurately and sensitively detect sudden load changes of the motor based on the operating parameters and / or changes in the operating parameters, and determine whether the motor has entered a heavy load state.

[0492] After the overload identification unit 221 identifies that the functional motor 211 has entered an overload state, the overload control unit 222 in the controller assembly 22 may select a second control strategy to control and adjust the functional motor 211. For example, the second control strategy may be selected to exit the overload state by reducing the duty cycle, reducing the speed, reducing or maintaining the current, reducing or maintaining the power, reducing or maintaining the torque, etc. The second control strategy may be the same as the first control strategy, or may be a control strategy different from the first control strategy.

[0493] In the electric work vehicle, the overload identification unit 221 in the controller component 22 monitors one or more operating parameters related to the functional motor 211, and determines whether the functional motor 211 has entered an overload state based on the operating parameters and / or changes in the operating parameters. If it is determined that the functional motor 211 has entered an overload state, the overload control unit 222 in the controller component 22 selects an appropriate control strategy according to the situation to adjust and control the functional motor 211 in a timely manner, so that the functional motor 211 exits the overload state. In this way, it is possible to accurately and sensitively identify the overload mutation of the motor, further quickly respond to the overload mutation, adjust the control strategy in a timely manner, and maintain the motor system in a normal operating state, thereby improving the stability and work efficiency of the entire machine and optimizing the user experience.

[0494] As shown in FIG18 , in an electric work vehicle provided in one or more optional embodiments of the present specification, the overload identification unit selects a target operating parameter from a plurality of operating parameters for monitoring, and determines whether the functional motor enters an overload state based on the target operating parameter and / or a change in the target operating parameter, including:

[0495] S101: Determine whether the speed parameter matches the current first control strategy.

[0496] S102 : In response to the rotational speed parameter not matching the first control strategy, the overload identification unit 221 is configured to select the rotational speed parameter as the target operating parameter.

[0497] The control strategy that matches the speed parameter is a speed closed-loop control strategy. If the control strategy currently adopted by the controller component 22 for the functional motor 211 is a non-speed closed-loop control strategy such as the current closed-loop control strategy, the power closed-loop control strategy, the torque closed-loop control strategy, or the PWM duty cycle open-loop control strategy, the heavy load identification unit 221 may select the speed parameter as the target operating parameter.

[0498] When selecting the target operating parameter, it is actually determined according to the current first control strategy. If the first control strategy is a non-speed closed-loop control strategy, the overload identification unit 221 can select the speed parameter as the target operating parameter.

[0499] S103: Determine whether the functional motor 211 has entered an overload state based on the speed parameter and / or the change in the speed parameter. The overload identification unit 221 selects the speed parameter as the target operating parameter and further monitors the speed parameter. The change in the speed parameter may include, for example, a difference in the speed parameter at different times, an increase or decrease rate of the speed parameter, etc.

[0500] As shown in FIG19 , in an electric working vehicle provided in one or more optional embodiments of this specification, the speed parameter includes a motor speed parameter. The method for the overload identification unit 221 to determine whether the functional motor 211 enters an overload state based on the speed parameter and / or the change in the speed parameter includes:

[0501] S201: During the operation of the functional motor, determine whether the motor speed parameter is greater than or equal to a corresponding preset motor speed parameter threshold.

[0502] The motor speed parameters include the motor speed, motor speed difference, and motor speed change rate of the functional motor 211. The preset motor speed parameter threshold corresponding to the motor speed is a motor speed threshold, the preset motor speed parameter threshold corresponding to the motor speed difference is a motor speed difference threshold, and the preset motor speed parameter threshold corresponding to the motor speed change rate is a motor speed change rate threshold.

[0503] The motor speed can be obtained by sampling the speed of the functional motor 211 .

[0504] The motor speed difference refers to the difference between the motor speeds of the functional motor 211 at two adjacent moments. In some optional embodiments, the motor speed difference ΔNk can be obtained by subtracting the motor speed Nk obtained at the current moment from the motor speed Nk-1 obtained at the previous moment. The motor speed difference can be an absolute value; that is, the obtained ΔNk is a positive number, which facilitates subsequent calculation of the ratio.

[0505] The motor speed change rate is used to characterize the change trend of the motor speed of the functional motor at a corresponding moment. The motor speed change rate may include the first-order derivative and the second-order derivative of the function of the motor speed changing with time.

[0506] In some optional embodiments, the motor speeds obtained at multiple moments can be fitted to obtain a motor speed curve, and the slope of the motor speed curve can be used as the motor speed change rate. In fact, the slope of the motor speed curve is the first-order derivative of the motor speed. In other optional embodiments, the slope of the motor speed curve can also be used as the motor speed change rate. In fact, the slope of the motor speed curve is the second-order derivative of the motor speed.

[0507] In some optional embodiments, the method for the overload identification unit 221 to determine whether the motor speed parameter is greater than or equal to a corresponding preset motor speed parameter threshold includes:

[0508] At least one motor speed parameter is obtained, and it is determined whether the at least one motor speed parameter is less than or equal to a corresponding preset motor speed parameter threshold.

[0509] The overload identification unit 221 can obtain one of the motor speed parameters, such as the motor speed, and compare the motor speed parameter with the corresponding preset motor speed parameter threshold, such as the motor speed threshold, to determine the size relationship between the motor speed parameter and the corresponding motor speed parameter threshold.

[0510] The overload identification unit 221 can obtain two of the motor speed parameters, such as the motor speed and the motor speed difference, and compare the two motor speed parameters with the corresponding two preset motor speed parameter thresholds, such as the motor speed threshold and the motor speed difference threshold, to determine the size relationship between the two motor speed parameters and their respective corresponding two preset motor speed parameter thresholds.

[0511] The overload identification unit 221 can obtain the above three motor speed parameters, compare the three motor speed parameters with the corresponding three preset motor speed parameter thresholds, and determine the size relationship between the three-phase motor speed parameters and the three corresponding preset motor speed parameter thresholds.

[0512] S202: In response to the motor speed parameter being greater than or equal to the corresponding preset motor speed parameter threshold, determining that the functional motor enters a heavy load state.

[0513] It should be noted that the overload identification unit 221 monitors and analyzes the corresponding operating parameters of the functional motor 211 during its operation. The operating process refers to the stable execution of the corresponding functional operation, excluding any changes in operating parameters caused by active user control. The operation of the functional motor 211 can significantly change under user control, such as during speed gear switching, the initial speed increase phase, and the speed reduction phase near the end of operation. Therefore, the operating process described in the embodiments of this specification does not include these stages.

[0514] Taking the motor speed as an example, FIG20 is a schematic diagram showing how the functional motor 211 determines a sudden overload change based on a motor speed threshold during operation.

[0515] The heavy load identification unit 221 can determine the current motor speed N of the functional motor 211. k Is it less than or equal to the corresponding motor speed threshold N T If so, it is determined that the functional motor 211 has entered a heavy-load state.

[0516] Furthermore, a time constraint condition can be added. Within a preset ΔT time (eg, 0.01 to 10 seconds), the current speed N k Less than or equal to the preset speed threshold N T , it is determined that the load has entered the heavy load operation area;

[0517] Furthermore, the time limit added above can be segmented, with X ΔTs preset. x Time, for example, set X = 4, ΔT0 = 10 seconds, ΔT1 = 1 second, ΔT2 = 0.1 seconds, ΔT3 = 0.01 seconds, within ΔT0 (10 seconds) the current speed N k Less than or equal to N T0 , and / or the current speed N within ΔT1 (1 second) k Less than or equal to N T1 , and / or the current speed N within ΔT2 (0.1 seconds) k Less than or equal to N T2 , and / or the current speed N within ΔT3 (0.01 seconds) k Less than or equal to N T3 , it is determined that the load has entered the heavy load operation area, N T0 ~N T3 Satisfying the relationship (1)NT0 ≥N T1 ≥N T2 ≥N T3 , or N T0 ≤N T1 ≤N T2 ≤N T3 .

[0518] It is understood that the functional motor 211 is provided with different speed gears. For example, under no-load conditions, the low speed is 2800 RPM, the mid-speed is 3000 RPM, and the high speed is 3200 RPM. The motor speed threshold can be set for different speed gears and can be set as an absolute value or a proportional value.

[0519] For the case where the threshold is set to an absolute value, the following example is shown:

[0520] (1) The speed thresholds of each gear are the same within the same time interval:

[0521] The low-gear speed threshold is 1500 RPM, the mid-gear speed threshold is 1500 RPM, and the high-gear speed threshold is 1500 RPM. After adding the time restriction condition, the speed thresholds for the same gear at different time intervals are shown in Table 9 below.

[0522] Table 9

[0523] (2) The speed thresholds of each gear are different within the same time interval:

[0524] The positive correlation threshold increases - the low-speed threshold is 1300RPM, the mid-speed threshold is 1400RPM, and the high-speed threshold is 1500RPM. After adding the time limit condition, the speed thresholds for the same gear at different time intervals are shown in Table 10 below.

[0525] Table 10

[0526] Alternatively, the negatively correlated thresholds decrease in a descending manner—the low-gear speed threshold is 1550 RPM, the mid-gear speed threshold is 1450 RPM, and the high-gear speed threshold is 1350 RPM. After adding the time restriction condition, the speed thresholds for the same gear at different time intervals are shown in Table 11 below.

[0527] Table 11

[0528] When the threshold is set as a proportional value, the following example is shown:

[0529] (1) The ratio of each gear is the same within the same time interval: the ratio is fixed at 50%, the low-speed threshold is 1400RPM, the medium-speed threshold is 1500RPM, and the high-speed threshold is 1600RPM. After adding the time limit condition, the speed thresholds of the same gear at different time intervals are as shown in Table 12 below.

[0530] Table 12

[0531] (2) The ratios of different levels are different within the same time interval:

[0532] Positive correlation ratio increases - the low gear ratio is 45%, the low gear speed threshold is 1260RPM, the mid-range ratio is 50%, the mid-range speed threshold is 1500RPM, the high gear ratio is 55%, and the high gear speed threshold is 1760RPM. After adding the time limit condition, the speed thresholds for the same gear at different time intervals are shown in Table 13 below.

[0533] Table 13

[0534] The negative correlation ratio decreases - the low gear ratio is 55%, the low gear speed threshold is 1540RPM, the mid-range ratio is 50%, the mid-range speed threshold is 1500RPM, the high gear ratio is 45%, and the high gear speed threshold is 1440RPM. After adding the time limit condition, the speed thresholds for the same gear at different time intervals are shown in Table 14 below.

[0535] Table 14

[0536] Taking the motor speed difference as an example, FIG21 is a schematic diagram showing how the functional motor 211 determines a sudden overload change based on the motor speed difference threshold during operation.

[0537] The motor speed difference is: the speed N obtained at the current moment k The speed N obtained at the previous moment k-1 Take the difference to get ΔN k The speed difference can be an absolute value, that is, the obtained ΔN k is a positive number, which makes it easier to calculate the ratio later.

[0538] The overload identification unit 221 can obtain the motor speed N at the current moment k The motor speed N obtained at the last moment k-1 Make the difference to get the motor speed difference ΔN k , if ΔN k Less than or equal to the preset motor speed difference threshold ΔN T , it is determined that the functional motor 211 has entered a heavy-load state.

[0539] Furthermore, a time constraint condition can be added. Within a preset ΔT time (eg, 0.01 to 10 seconds), the current speed difference ΔN k Less than or equal to the speed difference threshold ΔN T , it is determined that the load has entered the heavy load operation area;

[0540] Furthermore, the time limit added above can be segmented, with X ΔTs preset. x Time, for example, set X = 4, ΔT0 = 10 seconds, ΔT1 = 1 second, ΔT2 = 0.1 seconds, ΔT3 = 0.01 seconds, and the speed N obtained at the current moment k Compared with the speed N at the previous ΔT0 (10 seconds) g Take the difference to get ΔN kg , N k Compared with the speed N at the previous ΔT1 (1 second) h Take the difference to get ΔN kh , N k Compared with the speed N at the previous ΔT2 (0.1 second) i Take the difference to get ΔN ki , N k Compared with the speed N at the previous ΔT3 (0.01 seconds) j Take the difference to get ΔN kj , if ΔN kg Less than or equal to the preset speed difference threshold ΔN T0 , and / or ΔN kh Less than or equal to the preset speed difference threshold ΔN T1 , and / or ΔN ki Less than or equal to the preset speed difference threshold ΔN T2 , and / or ΔN kj Less than or equal to the preset speed difference threshold ΔN T3 , it is determined that the load has entered the heavy load operation area, ΔN T0 ~ΔN T3 Satisfying the relationship (2)ΔN T0 ≥ΔN T1 ≥ΔN T2 ≥ΔN T3 .

[0541] The motor speed threshold can be set for different speed gears and can be set as an absolute value or a proportional value.

[0542] For the case where the threshold is set to an absolute value, the following example is shown:

[0543] (1) The speed difference thresholds for each gear within the same time interval are the same: For example, the preset fixed difference is 1500RPM. After adding the time limit condition, the speed difference thresholds for the same gear at different time intervals are shown in Table 15 below.

[0544] Table 15

[0545] (2) The thresholds of the speed difference of each gear are different within the same time interval:

[0546] The positively correlated speed difference increases - the low-speed difference is 1400RPM, the mid-speed difference is 1500RPM, and the high-speed difference is 1600RPM. After adding the time limit condition, the speed difference thresholds for the same gear at different time intervals are shown in Table 16 below.

[0547] Table 16

[0548] The negatively correlated speed difference decreases - the low-speed difference is 1550RPM, the mid-speed difference is 1500RPM, and the high-speed difference is 1450RPM. After adding the time limit condition, the speed difference thresholds for the same gear at different time intervals are shown in Table 17 below.

[0549] Table 17

[0550] When the threshold is set as a proportional value, the following example is shown:

[0551] (1) The ratio of each gear is the same within the same time interval: the ratio is fixed at 50%. After adding the time limit condition, the speed difference threshold value of the same gear at different time intervals is shown in Table 18 below.

[0552] Table 18

[0553] (2) The ratios of different levels are different within the same time interval:

[0554] The positively correlated speed difference ratio increases - the low gear ratio is 45%, the low gear speed difference is 1260RPM, the mid-range ratio is 50%, the mid-range speed difference is 1500RPM, the high gear ratio is 55%, and the high-range speed difference is 1760RPM. After adding the time limit condition, the speed difference thresholds for the same gear at different time intervals are shown in Table 19 below.

[0555] Table 19

[0556] The negatively correlated speed difference ratio decreases - the low gear ratio is 55%, the low gear speed difference is 1540RPM, the mid-range ratio is 50%, the mid-range speed difference is 1500RPM, the high gear ratio is 45%, and the high gear speed difference is 1440RPM. After adding the time limit condition, the speed difference thresholds for the same gear at different time intervals are shown in Table 20 below.

[0557] Table 20

[0558] Taking the motor speed change rate as an example, FIG22 is a schematic diagram showing how the functional motor 211 determines a sudden overload change based on the motor speed change rate threshold during operation.

[0559] The overload identification unit 221 can determine whether the current motor speed change rate of the functional motor 211 is less than or equal to a corresponding preset motor speed change rate threshold. If so, it is determined that the functional motor 211 has entered an overload state.

[0560] Specifically, the overload identification unit 221 can obtain t0, t1, t2...t k The motor speed at the moment is N0, N1, N2...N k , N0, N1, N2…N k Perform linear fitting to obtain the corresponding curve slope k, which is calculated as follows: k = (Etn–Et*En) / [Et 2 –(Et) 2 ].

[0561] Among them, Etn represents the mathematical expectation of the product of sampling time t and speed, Et represents the mathematical expectation of sampling time t, En represents the mathematical expectation of speed, Et 2 Represents the mathematical expectation of the square of the sampling time t, (Et) 2 Represents the square of the mathematical expectation of the sampling time t.

[0562] Assume that Δt0=t1-t0, Δt1=t2-t1, Δt k =t k +1-t k In order to facilitate software calculation, it is generally designed as Δt0=Δt1=……=Δt k Therefore, the above formula can be simplified as follows: k=[n*Σ(t*n)–Σt*Σn] / [n*Σt 2 –Σt*Σt], where n is a positive integer. In order to further simplify the calculation process and reduce software calculation overhead, n in the above simplified formula can be set to 2 m , m is a positive integer.

[0563] When the slope k is less than or equal to the preset slope threshold kT , which means that the load is determined to have entered the heavy load operation area.

[0564] Furthermore, in order to obtain a better judgment effect, a speed filtering method can be added on the basis of the above. The added filtering methods mainly include: fixed window filtering, sliding window filtering, arithmetic mean filtering, de-extreme value average filtering, median filtering, etc. Different algorithms can be combined, such as fixed window arithmetic mean filtering, sliding window median filtering, etc. In this way, the above speeds N0, N1, N2...N k is the value obtained after filtering. Thus, when the fixed window filter series method is used, Δt0, Δt1, Δt2…Δt k The value is X speed sampling intervals. For example, when the speed is obtained every 1ms, the preset X=8, then the filtered value will be calculated every 8ms, Δt0=Δt1=Δt2=Δt k =8ms; When the sliding window filter series method is used, the above preset conditions are still applied, then Δt0=Δt1=Δt2=Δt k =1ms. After each fixed window filtering or sliding window filtering is completed, the slope k is calculated using formula (3), which is the first-order derivative value of the motor speed per unit time.

[0565] Furthermore, if the motor runs at a relatively large speed span, Δt0, Δt1, Δt2…Δt k The value of can be adjusted dynamically according to the current motor speed, because if Δt0, Δt1, Δt2…Δt k If it is too small, when the motor speed is relatively low, the speed sampling frequency is much higher than the motor speed filtering frequency, and the speed sampled at each moment may be the same, which wastes computing resources unnecessarily. Or, when the motor speed fluctuates on a small time scale, it is easy to interfere with the calculation result and cause misjudgment. If Δt0, Δt1, Δt2…Δt k If it is too large, when the motor speed is relatively high, the speed sampling is far lower than the actual speed change frequency, and the obtained data fluctuates greatly, or the actual speed change rate may meet the application requirements, but the actual calculation judgment fails to recognize it. Therefore, Δt0, Δt1, Δt2…Δt k The adjustment rule is that when the speed is high, the time interval is small, and when the speed is low, the time interval is large. There are three ways to adjust this time interval. The first is to adjust the speed sampling interval of 1ms, for example, to 0.5ms or 2ms. In this way, under the fixed window filter series method, Δt0 = Δt1 = Δt2 = Δt k =4ms or 16ms, under the sliding window filter series method, Δt0=Δt1=Δt2=Δt k=0.5ms or 2ms; the second is to adjust the window length (number of sampling points X), for example, to X=4 or X=16, so that under the fixed window filter series method Δt0=Δt1=Δt2=Δt k =4ms or 16ms, under the sliding window filter series method, Δt0=Δt1=Δt2=Δt k Still equal to 1ms; the third method is to adjust the speed sampling interval and the window length (number of sampling points X) at the same time. In addition, since the speed drop caused by a sudden change in load is also relatively fast, this process will not adjust Δt0, Δt1, Δt2...Δt k , the speed will be adjusted only after it stabilizes for a period of time.

[0566] Furthermore, after each fixed window filtering or sliding window filtering, the slope is calculated, so that a set of k0, k1, k2...k k , for k0, k1, k2…k k Then perform linear fitting to obtain the corresponding slope k', which is calculated as follows: k'=(Etk–Et*Ek) / [Et 2 –(Et) 2 ].

[0567] Wherein, Etk represents the mathematical expectation of the time t at which the speed slope is obtained each time and the speed slope, Et represents the mathematical expectation of the time t at which the speed slope is obtained each time, Ek represents the mathematical expectation of the speed slope, and Et 2 It represents the mathematical expectation of the square of the time t at which the speed slope is obtained each time, (Et) 2 Represents the square of the mathematical expectation of the sampling time t.

[0568] Since k0, k1, k2…k are obtained each time k The time intervals are equal, so Δt'0, Δt'1, Δt'2…Δt' k Therefore, the above formula can be simplified to: k'=[n'*Σ(t*k)–Σt*Σk] / [n'*Σt 2 –Σt*Σt], where n' is a positive integer. In order to further simplify the calculation process and reduce software calculation overhead, n' in the above simplified formula can be set to 2 m’ , m' is a positive integer. When the slope k' is less than or equal to the preset slope threshold k' T , that is, it is determined that the load has entered the heavy load operation area. Here, the slope k' is the second-order derivative of the motor speed per unit time.

[0569] In the case where the first-order derivative of the motor speed is selected as the motor speed change rate, the overload identification unit 221 compares the motor speed change rate with the corresponding preset speed first-order derivative threshold. If the motor speed change rate is less than or equal to the preset speed first-order derivative threshold, it can be determined that the functional motor 211 enters the overload state.

[0570] In the case where the second-order derivative of the motor speed is selected as the motor speed change rate, the overload identification unit 221 compares the motor speed change rate with the corresponding preset speed second-order derivative threshold value. If the motor speed change rate is less than or equal to the preset speed second-order derivative threshold value, it can be determined that the functional motor 211 enters the overload state.

[0571] In some optional embodiments, the overload identification unit 221 can also obtain multiple motor speed parameters, compare the multiple motor speed parameters with their corresponding preset motor speed parameter thresholds, and determine whether the multiple motor speed parameters are all less than or equal to the corresponding preset motor speed parameter thresholds.

[0572] For example, the motor speed is compared with a corresponding preset motor speed threshold, and the motor speed difference is compared with a corresponding preset motor speed difference threshold. If the motor speed is less than or equal to the preset motor speed threshold, and the motor speed difference is less than or equal to the preset motor speed difference threshold, it is determined that the functional motor 211 has entered the overload state.

[0573] For example, the motor speed, the motor speed difference, and the motor speed change rate are respectively compared with the corresponding preset motor speed threshold, the preset motor speed difference threshold, and the preset motor speed change rate threshold. If the three comparison results are all less than or equal to the corresponding threshold, it can be determined that the functional motor 211 has entered an overload state.

[0574] As shown in FIG23 , in an electric working vehicle provided in one or more optional embodiments of the present specification, the speed parameter includes a motor sector time parameter. The heavy load identification unit 221 determines whether the functional motor enters a heavy load state based on the speed parameter and / or the change in the speed parameter, including:

[0575] S301: During the operation of the functional motor, determine whether the motor sector time parameter is greater than or equal to a corresponding preset motor sector time parameter threshold.

[0576] The motor sector time parameters include the motor sector time, motor sector time difference and motor sector time change rate of the functional motor 211. The corresponding preset motor sector time parameter thresholds are the motor sector time threshold, the motor sector time difference threshold and the motor sector time change rate threshold.

[0577] The electrical cycle of the functional motor 211 includes multiple sectors, and the motor sector time refers to the corresponding duration of each sector. As shown in Figure 4, a schematic diagram of a sector time provided in an optional embodiment of this specification is shown. The functional motor 211 can be a three-phase brushless DC motor or a three-phase permanent magnet synchronous motor. The electrical cycle (360°) of the motor can be divided into multiple sectors. Generally, the electrical cycle is divided into 6 sectors on average, each sector has an electrical angle of 60°, and the motor sector time refers to the motor operation duration corresponding to each sector. Referring to Figure 4, taking a square wave driven brushless DC motor as an example, when the functional motor 211 is running smoothly, the time of each sector of the 360° electrical cycle (Δt0, Δt1, Δt2, Δt3, Δt4, Δt5) is relatively close, and when the load changes more drastically, the corresponding motor sector time will also undergo a sudden change.

[0578] The motor sector time difference refers to the difference between the motor sector time at two adjacent moments. In some optional embodiments, the overload identification unit 221 can obtain the sector time S at the current moment. k Compared with the sector time S obtained at the last moment k-1 Take the difference to get ΔS k The sector time difference can be an absolute value, that is, the obtained ΔS k is a positive number, which makes it easier to calculate the ratio later.

[0579] The motor sector time change rate is used to characterize the change trend of the motor sector time. The motor sector time change rate may include the first-order derivative and the second-order derivative of the function of the motor sector time changing with time.

[0580] In some optional embodiments, the motor sector time obtained at each moment can be fitted to obtain a motor sector time curve, and the slope of the motor sector time curve can be used as the motor sector time change rate. In fact, the slope of the motor sector time curve is the first-order derivative of the motor sector time. In other embodiments, the slope of the slope of the motor sector time curve can be used as the motor sector time change rate. In fact, the slope of the slope of the motor sector time curve is the second-order derivative of the motor sector time.

[0581] In some optional embodiments, the method in which the overload identification unit 221 determines whether the motor sector time parameter is greater than or equal to a corresponding preset motor sector time parameter threshold includes:

[0582] At least one motor sector time parameter is obtained, and it is determined whether the at least one motor sector time parameter is greater than or equal to a corresponding preset motor sector time parameter threshold.

[0583] The overload identification unit 221 can obtain one of the motor sector time parameters, such as the motor sector time, and compare the motor sector time parameter with the corresponding preset motor sector time parameter threshold, such as the motor sector time threshold, to determine the size relationship between the motor sector time parameter and the corresponding motor sector time parameter threshold.

[0584] The overload identification unit 221 can obtain two of the motor sector time parameters, such as the motor sector time and the motor sector time difference, and compare the two motor sector time parameters with the corresponding two preset motor sector time parameter thresholds, such as the motor sector time threshold and the motor sector time difference threshold, to determine the size relationship between the two motor sector time parameters and their respective corresponding two preset motor sector time parameter thresholds.

[0585] The overload identification unit 221 can obtain the above three motor sector time parameters, compare the three motor sector time parameters with the corresponding three preset motor sector time parameter thresholds, and determine the size relationship between the three-phase motor sector time parameters and the three corresponding preset motor sector time parameter thresholds.

[0586] S302: In response to the motor sector time parameter being greater than or equal to the corresponding preset motor sector time parameter threshold, determining that the functional motor enters a heavy load state.

[0587] Taking the motor sector time as an example, as shown in FIG24 , it is a schematic diagram of determining a sudden overload change based on the motor sector time threshold during the operation of the functional motor 211 .

[0588] The overload identification unit 221 can determine whether the current sector time Sk is greater than or equal to a preset sector time threshold ST. If so, it is determined that the functional motor 211 has entered an overload state.

[0589] Furthermore, a time restriction condition can be added. If the current sector time Sk is greater than or equal to a preset sector time threshold ST within a preset ΔT time (e.g., 0.01 to 10 seconds), it is determined that the load has entered the heavy load operation area.

[0590] Furthermore, the time limit added above can be segmented, and X ΔTx times are preset, for example, X=4, ΔT0=10 seconds, ΔT1=1 second, ΔT2=0.1 second, ΔT3=0.01 second, within ΔT0 (10 seconds), the current sector time Sk is greater than or equal to ST0, and / or within ΔT1 (1 second), the current sector time Sk is greater than or equal to ST1, and / or within ΔT2 (0.1 second), the current sector time Sk is greater than or equal to ST2, and / or within ΔT3 (0.01 second), the current sector time S k Greater than or equal to S T3 , it is determined that the load has entered the heavy load operation area, S T0 ~S T3 Satisfying the relationship (5)S T0 ≤S T1 ≤S T2 ≤S T3 , or S T0 ≥S T1 ≥S T2 ≥S T3 .

[0591] The motor sector time threshold can be set for different speed gears and can be set as an absolute value or a proportional value.

[0592] For the case where the threshold is set to an absolute value, the following example is shown:

[0593] (1) The time thresholds of each sector are the same within the same time interval:

[0594] The low-speed sector time threshold is 6667 μs / p, the mid-speed sector time threshold is 6667 μs / p, and the high-speed sector time threshold is 6667 μs / p, where p is the number of motor pole pairs. After adding the time restriction, the motor sector time thresholds for the same gear at different time intervals are shown in Table 21.

[0595] Table 21

[0596] (2) The time thresholds of different sectors are different within the same time interval:

[0597] Positive correlation thresholds increase in magnitude—the low-speed sector time threshold is 7692 / p, the mid-speed sector time threshold is 7143 / p, and the high-speed sector time threshold is 6667 / p, where p is the number of motor pole pairs. After adding time constraints, the sector time thresholds for the same gear at different time intervals are shown in Table 22 below.

[0598] Table 22

[0599] Alternatively, negatively correlated thresholds decrease in value—the low-speed sector time threshold is 6452 / p, the mid-speed sector time threshold is 6897 / p, and the high-speed sector time threshold is 7407 / p, where p is the number of motor pole pairs. After adding the time constraint, the sector time thresholds for the same gear at different time intervals are shown in Table 23.

[0600] Table 23

[0601] When the threshold is set as a proportional value, the following example is shown:

[0602] (1) The ratio of each level is the same within the same time interval:

[0603] The ratio is fixed at 50%. The low-speed sector time threshold is 7143 / p, the medium-speed sector time threshold is 6667 / p, and the high-speed sector time threshold is 6250 / p, where p is the number of motor pole pairs. After adding the time restriction condition, the sector time thresholds for the same gear at different time intervals are shown in Table 24 below.

[0604] Table 24

[0605] (2) The ratios of different levels are different within the same time interval:

[0606] Positively correlated proportions increase: the low-range proportion is 45%, the low-range sector time threshold is 7937 / p, the mid-range proportion is 50%, the mid-range sector time threshold is 6667 / p, and the high-range proportion is 55%, the high-range sector time threshold is 5682 / p, where p is the number of motor pole pairs. After adding time constraints, the sector time thresholds for the same gear at different time intervals are shown in Table 25 below.

[0607] Table 25

[0608] Alternatively, with decreasing negative correlation ratios, the low-range ratio is 55%, the low-range sector time threshold is 6494 / p, the mid-range ratio is 50%, the mid-range sector time threshold is 6667 / p, and the high-range ratio is 45%, the high-range sector time threshold is 6944 / p, where p is the number of motor pole pairs. After adding the time restriction condition, the sector time thresholds for the same gear at different time intervals are shown in Table 26 below.

[0609] Table 26

[0610] Taking the motor sector time difference as an example, as shown in FIG25 , it is a schematic diagram of determining a sudden overload change based on the motor sector time difference threshold during operation of the functional motor 211 .

[0611] The overload identification unit 221 can obtain the motor sector time S at the current moment kThe motor sector time S obtained at the last moment k-1 Take the difference to get ΔS k , if ΔS k Greater than or equal to the preset sector time difference threshold ΔS T , it is determined that the functional motor 211 has entered a heavy-load state.

[0612] Furthermore, a time constraint condition can be added. Within a preset ΔT time (eg, 0.01 to 10 seconds), the current sector time difference ΔS k Greater than or equal to the sector time difference threshold ΔS T , it is determined that the load has entered the heavy load operation area;

[0613] Furthermore, the time limit added above can be segmented, and X ΔTx times are preset, for example, X=4, ΔT0=10 seconds, ΔT1=1 second, ΔT2=0.1 seconds, and ΔT3=0.01 seconds. The sector time Sk obtained at the current moment is subtracted from the sector time Sg at the previous ΔT0 (10 seconds) moment to obtain ΔSkg, the sector time Sh at the previous ΔT1 (1 second) moment is subtracted to obtain ΔSkh, the sector time Si at the previous ΔT2 (0.1 second) moment is subtracted to obtain ΔSki, the sector time Sj at the previous ΔT3 (0.01 second) moment is subtracted to obtain ΔSkj, if ΔSkg is greater than or equal to the preset sector time difference threshold ΔS T0 , and / or ΔS kh Greater than or equal to the preset sector time difference threshold ΔS T1 , and / or ΔS ki Greater than or equal to the preset sector time difference threshold ΔS T2 , and / or ΔS kj Greater than or equal to the preset sector time difference threshold ΔS T3 , it is determined that the load has entered the heavy load operation area, ΔS T0 ~ΔS T3 Satisfying the relationship (6)ΔS T0 ≤ΔS T1 ≤ΔS T2 ≤ΔS T3 .

[0614] The motor sector time difference threshold can be set for different speed gears and can be set as an absolute value or a proportional value.

[0615] For the case where the threshold is set to an absolute value, the following example is shown:

[0616] (1) The threshold of the time difference of each sector within the same time interval is the same:

[0617] For example, the preset fixed difference is 6667 / p, where p is the number of motor pole pairs. After adding the time restriction condition, the motor sector time difference thresholds for the same gear at different time intervals are shown in Table 27 below.

[0618] Table 27

[0619] (2) The thresholds of the time difference between sectors within the same time interval are different:

[0620] The positive sector time difference increases in value: the low-range sector time difference is 7692 / p, the mid-range sector time difference is 7143 / p, and the high-range sector time difference is 6667 / p, where p is the number of motor pole pairs. After adding the time limit condition, the motor sector time difference thresholds for the same gear at different time intervals are shown in Table 28 below.

[0621] Table 28

[0622] Alternatively, the negatively correlated sector time difference values ​​decrease—the low-range sector time difference is 6452 / p, the mid-range sector time difference is 6667 / p, and the high-range sector time difference is 6897 / p, where p is the number of motor pole pairs. After adding the time restriction condition, the motor sector time difference thresholds for the same gear at different time intervals are shown in Table 29 below.

[0623] Table 29

[0624] When the threshold is set as a proportional value, the following example is shown:

[0625] (1) The ratio of each level is the same within the same time interval:

[0626] The ratio is fixed at 50%. After adding the time restriction condition, the motor sector time difference thresholds at the same gear at different time intervals are shown in Table 30 below.

[0627] Table 30

[0628] (2) The ratios of different levels are different within the same time interval:

[0629] The positive sector time difference ratio increases: the low-range ratio is 45%, the low-range sector time difference is 7143 / p, the mid-range ratio is 50%, the mid-range sector time difference is 6667 / p, and the high-range ratio is 55%, the high-range sector time difference is 5682 / p, where p is the number of motor pole pairs. After adding the time restriction condition, the motor sector time difference thresholds for the same gear at different time intervals are shown in Table 31 below.

[0630] Table 31

[0631] Alternatively, the negatively correlated sector time difference ratios decrease in descending order: the low-range ratio is 55%, with a low-range sector time difference of 6494 / p; the mid-range ratio is 50%, with a mid-range sector time difference of 6667 / p; the high-range ratio is 45%, with a high-range sector time difference of 6944 / p, where p is the number of motor pole pairs. After adding the time restriction, the motor sector time difference thresholds for the same gear at different time intervals are shown in Table 32 below.

[0632] Table 32

[0633] Taking the motor sector time change rate as an example, as shown in FIG26 , it is a schematic diagram of determining a sudden overload change based on the motor speed change rate threshold during the operation of the functional motor 211 .

[0634] The overload identification unit 221 can obtain t0, t1, t2...t k Motor sector time S0, S1, S2...S k , change S0, S1, S2…S k Perform linear fitting to obtain the corresponding curve slope k, which is calculated as follows: k = (Ets–Et*Es) / [Et 2 –(Et) 2 ].

[0635] Among them, Ets represents the mathematical expectation of the product of sampling time t and sector time, Et represents the mathematical expectation of sampling time t, Es represents the mathematical expectation of sector time, Et 2 Represents the mathematical expectation of the square of the sampling time t, (Et) 2 Represents the square of the mathematical expectation of the sampling time t.

[0636] Assume that Δt0=t1-t0, Δt1=t2-t1, Δt k =t k +1-t k In order to facilitate software calculation, it is generally designed as Δt0=Δt1=……=Δt k Therefore, the above formula can be simplified to: k=[n*Σ(t*s)–Σt*Σs] / [n*Σt 2 –Σt*Σt], where n is a positive integer. In order to further simplify the calculation process and reduce software calculation overhead, n in the above simplified formula can be set to 2 m , m is a positive integer. When m=1, the above formula degenerates to the difference in sector time of 1.7 sections.

[0637] When the slope k is greater than or equal to the preset slope threshold k T , which means that the load is determined to have entered the heavy load operation area.

[0638] Furthermore, in order to obtain a better judgment effect, a sector time filtering method can be added on the basis of the above. k is the value obtained after filtering. Thus, when the fixed window filter series method is used, Δt0, Δt1, Δt2…Δt k The value of is the sampling interval of X sector time. For example, when the sector time is obtained every 1ms, the preset X=8, then the filtered value will be calculated every 8ms, Δt0=Δt1=Δt2=Δt k =8ms; When the sliding window filter series method is used, the above preset conditions are still applied, then Δt0=Δt1=Δt2=Δt k =1ms. After each fixed window filtering or sliding window filtering is completed, the slope k is calculated using formula (7), which is the first-order derivative value of the sector time with respect to the unit time.

[0639] Furthermore, if the time span of the motor operation sector is relatively large, Δt0, Δt1, Δt2…Δt k The value of can be adjusted dynamically according to the current motor sector time, because if Δt0, Δt1, Δt2…Δt k If it is too small, when the motor sector time is relatively low, the frequency of sector time sampling is much higher than the frequency of motor sector time filtering. The sector time sampled at each moment may be the same, which wastes computing resources unnecessarily. Or, when the motor sector time fluctuates on a small time scale, it is easy to interfere with the calculation result and cause misjudgment. If Δt0, Δt1, Δt2…Δt k If it is too large, when the motor sector time is relatively high, the sector time sampling is far lower than the actual sector time change frequency, and the obtained data fluctuates greatly, or the actual sector time change rate may have met the application requirements, but the actual calculation judgment fails to recognize it. Therefore, Δt0, Δt1, Δt2…Δt k The adjustment rule is that when the sector time is high, the time interval is small, and when the sector time is low, the time interval is large. There are three ways to adjust this time interval. The first is to adjust the above 1ms sector time sampling interval, for example, to 0.5ms or 2ms. In this way, under the fixed window filter series method, Δt0 = Δt1 = Δt2 = Δt k =4ms or 16ms, under the sliding window filter series method, Δt0=Δt1=Δt2=Δt k =0.5ms or 2ms; the second is to adjust the window length (number of sampling points X), for example, to X=4 or X=16, so that under the fixed window filter series method Δt0=Δt1=Δt2=Δt k=4ms or 16ms, under the sliding window filter series method, Δt0=Δt1=Δt2=Δt k Still equal to 1ms; the third method is to adjust the sector time sampling interval and the window length (number of sampling points X) at the same time. In addition, since the change of sector time decreases rapidly when the load suddenly changes, this process will not adjust Δt0, Δt1, Δt2...Δt k , the sector time will be adjusted only after it has been stable for a period of time.

[0640] Furthermore, after each fixed window filtering or sliding window filtering, the slope is calculated, so that a set of k0, k1, k2...k k , for k0, k1, k2…k k Then perform linear fitting to obtain the corresponding slope k', which is calculated as follows: k'=(Etk–Et*Ek) / [Et 2 –(Et) 2 ].

[0641] Wherein, Etk represents the mathematical expectation of the time t at which the sector time slope is obtained each time and the sector time slope, Et represents the mathematical expectation of the time t at which the sector time slope is obtained each time, Ek represents the mathematical expectation of the sector time slope, and Et 2 The mathematical expectation of the square of the time slope of each sector is obtained at time t, (Et) 2 Represents the square of the mathematical expectation of the sampling time t.

[0642] Since k0, k1, k2…k are obtained each time k The time intervals are equal, so Δt'0, Δt'1, Δt'2…Δt' k Therefore, the above formula can be simplified to: k'=[n'*Σ(t*k)–Σt*Σk] / [n'*Σt 2 –Σt*Σt], where n' is a positive integer. In order to further simplify the calculation process and reduce software calculation overhead, n' in the above simplified formula can be set to 2 m’ , m' is a positive integer. When the slope k' is greater than or equal to the preset slope threshold k' T , which means the load has entered the heavy load operation area. Here, the slope k' is the second-order derivative of the sector time with respect to the unit time.

[0643] In the case where the first-order derivative of the motor sector time is selected as the motor sector time change rate, the overload identification unit 221 compares the motor sector time change rate with the corresponding preset speed first-order derivative threshold. If the motor sector time change rate is less than or equal to the preset speed first-order derivative threshold, it can be determined that the functional motor 211 enters the overload state.

[0644] In the case where the second-order derivative of the motor sector time is selected as the motor sector time change rate, the overload identification unit 221 compares the motor sector time change rate with the corresponding preset speed second-order derivative threshold. If the motor sector time change rate is less than or equal to the preset speed second-order derivative threshold, it can be determined that the functional motor 211 has entered an overload state.

[0645] In some optional embodiments, the overload identification unit 221 can also obtain multiple motor sector time parameters, compare the multiple motor sector time parameters with their corresponding preset motor sector time parameter thresholds, and determine whether the multiple motor sector time parameters are all less than or equal to the corresponding preset motor sector time parameter thresholds.

[0646] For example, the motor sector time is compared with a corresponding preset motor sector time threshold, and the motor sector time difference is compared with a corresponding preset motor sector time difference threshold. If the motor sector time is less than or equal to the preset motor sector time threshold, and the motor sector time difference is less than or equal to the preset motor sector time difference threshold, it is determined that the functional motor 211 has entered the overload state.

[0647] For example, the motor sector time, the motor sector time difference, and the motor sector time change rate are respectively compared with the corresponding preset motor sector time threshold, the preset motor sector time difference threshold, and the preset motor sector time change rate threshold. If the three comparison results are all less than or equal to the corresponding thresholds, it can be determined that the functional motor 211 has entered an overload state.

[0648] As shown in FIG. 27 , in an electric work vehicle provided in one or more optional embodiments of the present specification, the overload identification unit selects a target operating parameter from a plurality of operating parameters for monitoring, and determines whether the functional motor enters an overload state based on the target operating parameter and / or a change in the target operating parameter, including:

[0649] S401: Determine whether the electrical parameter matches the current first control strategy.

[0650] S402: In response to the electrical parameter not matching the first control strategy, the overload identification unit is configured to select the electrical parameter as the target operating parameter.

[0651] The control strategy matched to the electrical parameter is a current closed-loop control strategy. If the control strategy currently adopted by the controller component 22 for the functional motor 211 is a non-current closed-loop control strategy such as the speed closed-loop control strategy, the power closed-loop control strategy, the torque closed-loop control strategy, or the PWM duty cycle open-loop control strategy, the heavy load identification unit 221 may select the electrical parameter as the target operating parameter.

[0652] When selecting the target operating parameters, they are actually determined based on the current first control strategy. If the first control strategy is a non-current closed-loop control strategy, the overload identification unit 221 can select the electrical parameters as the target operating parameters.

[0653] S403: Determine whether the functional motor has entered an overload state based on the electrical parameter and / or the change in the electrical parameter. The overload identification unit 221 selects the electrical parameter as the target operating parameter and further monitors the electrical parameter. The change in the electrical parameter may include, for example, the difference between the electrical parameter at different times, the rate of increase or decrease of the electrical parameter, etc.

[0654] As shown in FIG28 , in an electric working vehicle provided in one or more optional embodiments of this specification, the method of the overload identification unit 221 determining whether the functional motor 211 enters an overload state based on the electrical parameters and / or changes in the electrical parameters includes:

[0655] S501: During the operation of the functional motor, determine whether the electrical parameter is greater than or equal to a corresponding preset electrical parameter threshold.

[0656] S502: In response to the electrical parameter being greater than or equal to the corresponding preset electrical parameter threshold, determining that the functional motor enters a heavy load state.

[0657] In some optional embodiments, the electrical parameter includes a bus current parameter. The bus current parameter includes a bus current, a bus current difference, and a bus current change rate. The preset electrical parameter thresholds corresponding to the bus current, the bus current difference, and the bus current change rate are a bus current threshold, a bus current difference threshold, and a bus current change rate threshold, respectively.

[0658] The bus current can be determined by sampling using a current sampling resistor provided in the corresponding control circuit of the functional motor 211, or by sampling using a current sensor provided in the control circuit.

[0659] The bus current difference refers to the difference between the bus currents of the functional motor at two adjacent moments. The heavy load identification unit 221 can obtain the bus current B k Compared with the bus current B obtained at the previous moment k-1 Take the difference to get ΔB k The busbar current difference can be an absolute value, that is, the obtained ΔB k is a positive number, which makes it easier to calculate the ratio later.

[0660] The bus current change rate is used to characterize the changing trend of the bus current of the functional motor 211 at a corresponding moment. The bus current change rate may include the first-order derivative and the second-order derivative of the bus current change function over time. A bus current change curve can be obtained by fitting the bus currents sampled and determined at multiple moments, and the slope of the change curve is used as the bus current change rate. In fact, the slope of the change curve is the first-order derivative of the bus current. Alternatively, the slope of the bus current change curve is used as the bus current change rate. In fact, the slope of the change curve is the second-order derivative of the bus current.

[0661] The overload identification unit 221 determines whether the electrical parameter is greater than or equal to the corresponding preset electrical parameter threshold method, including: obtaining at least one bus current parameter, and determining whether the at least one bus current parameter is greater than or equal to the corresponding preset electrical parameter threshold.

[0662] Taking the bus current as an example, as shown in FIG29 , it is a schematic diagram of determining a sudden overload change based on the bus current threshold during operation of the functional motor 211 .

[0663] The heavy load identification unit 221 can determine the current bus current I k Is it greater than or equal to a preset bus current threshold I T If so, it is determined that the functional motor 211 has entered a heavy-load state.

[0664] Furthermore, a time constraint condition can be added. Within a preset ΔT time (for example, 0.01 to 10 seconds), the current bus current I k Greater than or equal to the preset bus current threshold I T , it is determined that the load has entered the heavy load operation area;

[0665] Furthermore, the time limit added above can be segmented, with X ΔTs preset. x Time, for example, set X = 4, ΔT0 = 10 seconds, ΔT1 = 1 second, ΔT2 = 0.1 seconds, ΔT3 = 0.01 seconds, within ΔT0 (10 seconds) the current bus current I k Greater than or equal to I T0, and / or the current bus current I within ΔT1 (1 second) k Greater than or equal to I T1 , and / or the current bus current I within ΔT2 (0.1 seconds) k Greater than or equal to I T2 , and / or the current bus current I within ΔT3 (0.01 seconds) k Greater than or equal to I T3 , it is determined that the load has entered the heavy load operation area, I T0 ~I T3 Satisfying the relationship (9)I T0 ≤I T1 ≤I T2 ≤I T3 , or the relation I T0 ≤I T1 ≤I T2 ≤I T3 .

[0666] The bus current threshold can be set for different speed gears and can be set as an absolute value or a proportional value.

[0667] For the case where the threshold is set to an absolute value, the following example is shown:

[0668] (1) The bus current thresholds of each gear are the same within the same time interval.

[0669] After adding the time restriction condition, the bus current thresholds at the same gear at different time intervals are shown in Table 33 below.

[0670] Table 33

[0671] (2) The bus current thresholds of different gears are different within the same time interval:

[0672] The positive correlation threshold increases. After adding the time limit condition, the bus current thresholds at the same gear at different time intervals are shown in Table 34 below.

[0673] Alternatively, the negative correlation threshold decreases. After adding the time limit condition, the bus current thresholds at the same gear at different time intervals are shown in Table 35 below.

[0674] Table 34

[0675] When the threshold is set as a proportional value, the following example is shown:

[0676] (1) The ratio of each gear is the same within the same time interval. After adding the time limit condition, the bus current threshold at the same gear in different time intervals is shown in Table 35 below

[0677] Table 35

[0678] (2) The ratios of different levels are different within the same time interval:

[0679] After adding the time limit condition, the bus current threshold at the same gear at different time intervals is shown in Table 36 below

[0680] Table 36

[0681] Or, the negative correlation ratio decreases. After adding the time limit condition, the bus current threshold at the same gear at different time intervals is shown in the following table 37

[0682] Table 37

[0683] Taking the bus current difference as an example, as shown in FIG30 , it is a schematic diagram of determining a sudden overload change based on the bus current difference threshold value during operation of the functional motor 211 .

[0684] The heavy load identification unit 221 can obtain the bus current I k Compared with the bus current I obtained at the previous moment k-1 Take the difference to get ΔI k , if ΔI k Greater than or equal to the preset bus current difference threshold ΔI T , it is determined that the load has entered the heavy load operation area;

[0685] Furthermore, a time constraint condition can be added. Within a preset ΔT time (eg, 0.01 to 10 seconds), the current bus current difference ΔI k Greater than or equal to the bus current difference threshold ΔI T , it is determined that the load has entered the heavy load operation area;

[0686] Furthermore, the time limit added above can be segmented, with X ΔTs preset. x Time, for example, set X = 4, ΔT0 = 10 seconds, ΔT1 = 1 second, ΔT2 = 0.1 seconds, ΔT3 = 0.01 seconds, and the bus current I obtained at the current moment k Compared with the bus current I at the previous ΔT0 (10 seconds) g Take the difference to get ΔI kg , will I k Compared with the bus current I at the previous ΔT1 (1 second) h Take the difference to get ΔI kh , will I k Compared with the bus current I at the previous ΔT2 (0.1 second) iTake the difference to get ΔI ki , will I k Compared with the bus current I at the previous ΔT3 (0.01 second) j Take the difference to get ΔI kj , if ΔI kg Greater than or equal to the preset bus current difference threshold ΔI T0 , and / or ΔI kh Greater than or equal to the preset bus current difference threshold ΔI T1 , and / or ΔI ki Greater than or equal to the preset bus current difference threshold ΔI T2 , and / or ΔI kj Greater than or equal to the preset bus current difference threshold ΔI T3 , it is determined that the load has entered the heavy load operation area, ΔI T0 ~ΔI T3 Satisfying the relationship (10)ΔI T0 ≥ΔI T1 ≥ΔI T2 ≥ΔI T3 .

[0687] The bus current difference threshold can be set for different speed gears and can be set as an absolute value or a proportional value.

[0688] For the case where the threshold is set to an absolute value, the following example is shown:

[0689] (1) The threshold value of the bus current difference of each gear is the same within the same time interval.

[0690] After adding the time restriction condition, the bus current difference thresholds at the same gear at different time intervals are shown in Table 38 below.

[0691] Table 38

[0692] (2) The thresholds of the bus current differences at different levels are different within the same time interval.

[0693] The positively correlated bus current difference increases. After adding the time limit condition, the bus current difference thresholds for the same gear at different time intervals are shown in Table 39 below.

[0694] Table 39

[0695] Alternatively, the negatively correlated bus current difference decreases. After adding the time limit condition, the bus current difference thresholds for the same gear at different time intervals are shown in Table 40 below.

[0696] Table 40

[0697] When the threshold is set as a proportional value, the following example is shown:

[0698] (1) The ratio of each gear is the same within the same time interval.

[0699] After adding the time restriction condition, the bus current difference thresholds at the same gear at different time intervals are shown in Table 41 below.

[0700] Table 41

[0701] (2) The ratios of different levels are different within the same time interval:

[0702] The positively correlated bus current difference ratio increases. After adding the time limit condition, the bus current difference thresholds at the same gear at different time intervals are shown in Table 42 below.

[0703] Table 42

[0704] Alternatively, the negatively correlated bus current difference ratio decreases. After adding the time limit condition, the bus current difference thresholds for the same gear at different time intervals are shown in Table 43 below.

[0705] Table 43

[0706] Taking the bus current change rate as an example, as shown in FIG31 , it is a schematic diagram of determining a heavy load mutation based on the bus current change rate threshold during operation of the functional motor 211 .

[0707] The overload identification unit 221 obtains t0, t1, t2...t k The bus current I0, I1, I2…I k , I0, I1, I2…I k Perform linear fitting to obtain the corresponding curve slope k, which is calculated as follows: k = (Eti–Et*Ei) / [Et 2 –(Et) 2 ].

[0708] Among them, Eti represents the mathematical expectation of the product of the sampling time t and the bus current, Et represents the mathematical expectation of the sampling time t, Ei represents the mathematical expectation of the bus current, and Et 2 The mathematical expectation of the square of the sampling time t, (Et) 2 Represents the square of the mathematical expectation of the sampling time t.

[0709] Assume that Δt0=t1-t0, Δt1=t2-t1, Δt k =t k +1-t k In order to facilitate software calculation, it is generally designed as Δt0=Δt1=……=Δtk Therefore, the above formula can be simplified as follows: k=[n*Σ(t*i)–Σt*Σi] / [n*Σt 2 –Σt*Σt], where n is a positive integer. In order to further simplify the calculation process and reduce software calculation overhead, n in the above simplified formula can be set to 2 m , m is a positive integer.

[0710] When the slope k is greater than or equal to the preset slope threshold k T , which means that the load is determined to have entered the heavy load operation area.

[0711] Furthermore, in order to obtain a better judgment effect, a bus current filtering method can be added on the basis of the above. k is the value obtained after filtering. Thus, when the fixed window filter series method is used, Δt0, Δt1, Δt2…Δt k The value is X bus current sampling intervals. For example, when the bus current is obtained every 1ms, the preset X=8, then the filtered value will be calculated every 8ms, Δt0=Δt1=Δt2=Δt k =8ms; When the sliding window filter series method is used, the above preset conditions are still applied, then Δt0=Δt1=Δt2=Δt k =1ms. After each fixed window filtering or sliding window filtering is completed, the slope k is calculated using the above formula, which is the first-order derivative value of the bus current per unit time.

[0712] Furthermore, if the bus current span of the motor is relatively large, Δt0, Δt1, Δt2…Δt k The value of can be adjusted dynamically according to the current motor bus current, because if Δt0, Δt1, Δt2…Δt k If it is too small, when the motor bus current is relatively low, the bus current sampling frequency is much higher than the motor bus current filtering frequency, and the bus current sampled at each moment may be the same, which wastes computing resources unnecessarily. Or, when the motor bus current fluctuates on a small time scale, it is easy to interfere with the calculation result and cause misjudgment. If Δt0, Δt1, Δt2…Δt k If it is too large, when the motor bus current is relatively high, the bus current sampling is far lower than the actual bus current change frequency, and the obtained data fluctuates greatly, or the actual bus current change rate may have met the application requirements, but the actual calculation judgment fails to recognize it. Therefore, Δt0, Δt1, Δt2…Δt kThe adjustment rule is that when the bus current is high, the time interval is small, and when the bus current is low, the time interval is large. There are three ways to adjust this time interval. The first is to adjust the bus current sampling interval of 1ms, for example, to 0.5ms or 2ms. In this way, under the fixed window filter series method, Δt0 = Δt1 = Δt2 = Δt k =4ms or 16ms, under the sliding window filter series method, Δt0=Δt1=Δt2=Δt k =0.5ms or 2ms; the second is to adjust the window length (number of sampling points X), for example, to X=4 or X=16, so that under the fixed window filter series method Δt0=Δt1=Δt2=Δt k =4ms or 16ms, under the sliding window filter series method, Δt0=Δt1=Δt2=Δt k The third method is to adjust the bus current sampling interval and the window length (number of sampling points X) at the same time. In addition, since the bus current drops rapidly when the load suddenly changes, this process will not adjust Δt0, Δt1, Δt2…Δt k , the adjustment will be made only after the bus current is stable for a period of time.

[0713] Furthermore, after each fixed window filtering or sliding window filtering, the slope is calculated using the above calculation formula, so that a set of k0, k1, k2...k k , for k0, k1, k2…k k Then perform linear fitting to obtain the corresponding slope k', which is calculated as follows: k'=(Etk–Et*Ek) / [Et 2 –(Et) 2 ].

[0714] Wherein, Etk represents the mathematical expectation of the time t at which the bus current slope is obtained each time and the bus current slope, Et represents the mathematical expectation of the time t at which the bus current slope is obtained each time, Ek represents the mathematical expectation of the bus current slope, and Et 2 It represents the mathematical expectation of the square of the moment t at which the bus current slope is obtained each time, (Et) 2 The square of the mathematical expectation at sampling time t.

[0715] Since k0, k1, k2…k are obtained each time k The time intervals are equal, so Δt'0, Δt'1, Δt'2…Δt' k Therefore, the above formula can be simplified to: k'=[n'*Σ(t*k)–Σt*Σk] / [n'*Σt 2–Σt*Σt], where n' is a positive integer. In order to further simplify the calculation process and reduce software calculation overhead, n' in the above simplified formula can be set to 2 m’ , m' is a positive integer. When the slope k' is greater than or equal to the preset slope threshold k' T , which means the load has entered the heavy load operation area. Here, the slope k' is the second-order derivative of the bus current per unit time.

[0716] In the case where the first-order derivative of the bus current is selected as the bus current change rate, the overload identification unit 221 compares the bus current change rate with the corresponding preset speed first-order derivative threshold. If the bus current change rate is less than or equal to the preset speed first-order derivative threshold, it can be determined that the functional motor 211 enters an overload state.

[0717] In the case where the second-order derivative of the bus current is selected as the bus current change rate, the overload identification unit 221 compares the bus current change rate with the corresponding preset speed second-order derivative threshold. If the bus current change rate is less than or equal to the preset speed second-order derivative threshold, it can be determined that the functional motor 211 enters an overload state.

[0718] In some optional embodiments, the overload identification unit 221 can also obtain multiple bus current parameters, compare the multiple bus current parameters with their corresponding preset bus current parameter thresholds, and determine whether the multiple bus current parameters are all less than or equal to the corresponding preset bus current parameter thresholds.

[0719] For example, the bus current is compared with a corresponding preset bus current threshold, and the bus current difference is compared with a corresponding preset bus current difference threshold. If the bus current is greater than or equal to the preset bus current threshold, and the bus current difference is greater than or equal to the preset bus current difference threshold, it is determined that the functional motor 211 has entered the overload state.

[0720] For example, the bus current, the bus current difference, and the bus current change rate are respectively compared with the corresponding preset bus current threshold, the preset bus current difference threshold, and the preset bus current change rate threshold. If the three comparison results are all greater than or equal to the corresponding thresholds, it can be determined that the functional motor 211 has entered an overload state.

[0721] In some optional embodiments, the electrical parameters include phase current parameters. The phase current parameters include phase current, phase current difference, and phase current rate of change. The preset electrical parameter thresholds corresponding to the phase current, the phase current difference, and the phase current rate of change are, respectively, a phase current threshold, a phase current difference threshold, and a phase current rate of change threshold.

[0722] The phase current refers to the current of the conducting phase of the functional motor 211. A current sensor or a current sampling resistor can be used to sample and determine the phase current. Considering that the phase current has an alternating current characteristic, the amplitude, peak-to-peak value, or effective value of the conducting phase current can be used as the phase current.

[0723] The current can be sampled and determined by using a current sampling resistor provided in the corresponding control circuit of the functional motor 211, or by using a current sensor provided in the control circuit.

[0724] The phase current difference refers to the difference between the phase currents of the functional motor at two adjacent moments. The overload identification unit 221 can obtain the phase current C k Compared with the phase current C obtained at the previous moment k-1 Take the difference to get ΔC k The phase current difference can be an absolute value, that is, the obtained ΔC k is a positive number, which makes it easier to calculate the ratio later.

[0725] The phase current change rate is used to characterize the changing trend of the phase current of the functional motor 211 at a corresponding moment. The phase current change rate may include the first-order derivative and the second-order derivative of the phase current change function over time. A phase current change curve can be obtained by fitting the phase currents sampled and determined at multiple moments. The slope of this change curve is used as the phase current change rate. In fact, the slope of this change curve is the first-order derivative of the phase current. Alternatively, the slope of the phase current change curve is used as the phase current change rate. In fact, the slope of the change curve is the second-order derivative of the phase current.

[0726] In some optional embodiments, the overload identification unit 221 determines whether the electrical parameter is greater than or equal to the corresponding preset electrical parameter threshold value, including: obtaining at least one phase current parameter, and determining whether the at least one phase current parameter is greater than or equal to the corresponding preset electrical parameter threshold value.

[0727] In some optional embodiments, the overload identification unit 221 can also obtain multiple phase current parameters, compare the multiple phase current parameters with their corresponding preset phase current parameter thresholds, and determine whether the multiple phase current parameters are all greater than or equal to the corresponding preset phase current parameter thresholds.

[0728] For example, the phase current is compared with a corresponding preset phase current threshold, and the phase current difference is compared with a corresponding preset phase current difference threshold. If the phase current is greater than or equal to the preset phase current threshold, and the phase current difference is greater than or equal to the preset phase current difference threshold, it is determined that the functional motor 211 has entered the overload state.

[0729] For example, the phase current, the phase current difference, and the phase current change rate are respectively compared with the corresponding preset phase current threshold, preset phase current difference threshold, and preset phase current change rate threshold. If the three comparison results are all greater than or equal to the corresponding thresholds, it can be determined that the functional motor 211 has entered an overload state.

[0730] In some optional embodiments, the electrical parameters include bus voltage parameters. The bus voltage parameters include bus voltage drop, bus voltage drop difference, and bus voltage drop change rate. The preset electrical parameter thresholds corresponding to the bus voltage drop, the bus voltage drop difference, and the bus voltage drop change rate are, respectively, a bus voltage drop threshold, a bus voltage drop difference threshold, and a bus voltage drop change rate threshold.

[0731] The bus voltage drop refers to the relative value of the voltage drop on the bus side of the functional motor 211, that is, the bus voltage drop during the operation of the functional motor 211 compared to the bus voltage before the start of the operation.

[0732] The bus voltage drop difference refers to the difference in bus voltage drop of the functional motor at two adjacent moments;

[0733] The bus voltage drop change rate is used to characterize the changing trend of the bus voltage drop of the functional motor 211 at a given moment. The bus voltage drop change rate can include the first-order derivative and second-order derivative of the bus voltage drop time-varying function. A bus voltage drop change curve can be obtained by fitting the bus voltage drops sampled and determined at multiple moments. The slope of this change curve is used as the bus voltage drop change rate. In fact, the slope of this change curve is the first-order derivative of the bus voltage drop. Alternatively, the slope of the bus voltage drop change curve can be used as the bus voltage drop change rate. In fact, the slope of the change curve is the second-order derivative of the bus voltage drop.

[0734] In some optional embodiments, the overload identification unit 221 determines whether the electrical parameter is greater than or equal to the corresponding preset electrical parameter threshold value, including: obtaining at least one bus voltage parameter, and determining whether the at least one bus voltage parameter is greater than or equal to the corresponding preset electrical parameter threshold value.

[0735] In some optional embodiments, the overload identification unit 221 can also obtain multiple bus voltage parameters, compare the multiple bus voltage parameters with their corresponding preset bus voltage parameter thresholds, and determine whether the multiple bus voltage parameters are all greater than or equal to the corresponding preset bus voltage parameter thresholds.

[0736] For example, the bus voltage drop is compared with a corresponding preset bus voltage drop threshold, and the bus voltage drop difference is compared with a corresponding preset bus voltage drop difference threshold. If the bus voltage drop is greater than or equal to the preset bus voltage drop threshold, and the bus voltage drop difference is greater than or equal to the preset bus voltage drop difference threshold, it is determined that the functional motor 211 has entered the overload state.

[0737] For example, the bus voltage drop, the bus voltage drop difference, and the bus voltage drop change rate are respectively compared with the corresponding preset bus voltage drop threshold, the preset bus voltage drop difference threshold, and the preset bus voltage drop change rate threshold. If the three comparison results are all greater than or equal to the corresponding thresholds, it can be determined that the functional motor 211 has entered an overload state.

[0738] Taking the bus voltage drop as an example, as shown in FIG32 , it is a schematic diagram of determining a heavy load mutation based on the bus voltage drop threshold during operation of the functional motor 211 .

[0739] The heavy load identification unit 221 can determine the load condition based on the relative change in bus voltage. The greater the load, the greater the relative voltage drop, and vice versa. In a battery-powered electric vehicle, the greater the load, the more significant the drop in battery pack terminal voltage. The terminal voltage corresponds to the bus voltage, and the bus voltage can reflect the battery pack terminal voltage. The relationship between bus voltage and current is shown in Figure 32.

[0740] In some optional embodiments, the electrical parameters include conduction phase voltage parameters. The conduction phase voltage parameters include a conduction phase voltage drop, a conduction phase voltage drop difference, and a conduction phase voltage drop change rate. The preset electrical parameter thresholds corresponding to the conduction phase voltage drop, the conduction phase voltage drop difference, and the conduction phase voltage drop change rate are, respectively, a conduction phase voltage drop threshold, a conduction phase voltage drop difference threshold, and a conduction phase voltage drop change rate threshold.

[0741] The conduction phase voltage drop refers to the relative value of the bus voltage drop of the functional motor 211, that is, the bus voltage drop during the operation of the functional motor 211 compared to the bus voltage before the start of the operation.

[0742] The conduction phase voltage drop difference refers to the difference between the conduction phase voltage drops of the functional motor at two adjacent moments;

[0743] The conduction phase voltage drop change rate is used to characterize the trend of change in the conduction phase voltage drop of the functional motor 211 at a given moment. The conduction phase voltage drop change rate can include the first-order derivative and second-order derivative of the conduction phase voltage drop time-varying function. A conduction phase voltage drop change curve can be obtained by fitting the conduction phase voltage drops sampled and determined at multiple moments. The slope of this change curve is used as the conduction phase voltage drop change rate. In fact, the slope of this change curve is the first-order derivative of the conduction phase voltage drop. Alternatively, the slope of the conduction phase voltage drop change curve can be used as the conduction phase voltage drop change rate. In fact, the slope of the slope of the change curve is the second-order derivative of the conduction phase voltage drop.

[0744] In some optional embodiments, the overload identification unit 221 determines whether the electrical parameter is greater than or equal to the corresponding preset electrical parameter threshold method, including: obtaining at least one conduction phase voltage parameter, and determining whether the at least one conduction phase voltage parameter is greater than or equal to the corresponding preset electrical parameter threshold.

[0745] In some optional embodiments, the overload identification unit 221 can also obtain multiple conduction phase voltage parameters, compare the multiple conduction phase voltage parameters with their corresponding preset conduction phase voltage parameter thresholds, and determine whether the multiple conduction phase voltage parameters are all greater than or equal to the corresponding preset conduction phase voltage parameter thresholds.

[0746] For example, the conduction phase voltage drop is compared with a corresponding preset conduction phase voltage drop threshold, and the conduction phase voltage drop difference is compared with a corresponding preset conduction phase voltage drop difference threshold. If the conduction phase voltage drop is greater than or equal to the preset conduction phase voltage drop threshold, and the conduction phase voltage drop difference is greater than or equal to the preset conduction phase voltage drop difference threshold, it is determined that the functional motor 211 has entered the heavy load state.

[0747] For example, the conduction phase voltage drop, the conduction phase voltage drop difference, and the conduction phase voltage drop change rate are respectively compared with the corresponding preset conduction phase voltage drop threshold, the preset conduction phase voltage drop difference threshold, and the preset conduction phase voltage drop change rate threshold. If the three comparison results are all greater than or equal to the corresponding thresholds, it can be determined that the functional motor 211 has entered the overload state.

[0748] Taking the conduction phase voltage drop as an example, FIG33 is a schematic diagram showing how the functional motor 211 determines a heavy load mutation based on the conduction phase voltage drop threshold during operation.

[0749] The heavy load identification unit 221 can judge based on the relative value of the voltage change of the conduction phase voltage within a commutation cycle. When the load increases, the instantaneous current (bus instantaneous current or phase instantaneous current) will increase, so that the voltage will change within a commutation cycle of the phase voltage, the amplitude of the voltage change and the conduction phase voltage drop. As shown in Figure 33, ΔV1 represents the conduction phase voltage drop. The heavy load identification unit 221 compares the conduction phase voltage drop with the corresponding preset conduction phase voltage drop threshold. If the conduction phase voltage drop is greater than or equal to the conduction phase voltage drop difference, it can be determined that the functional motor 211 has entered an overload state.

[0750] In some optional embodiments, the electrical parameter includes a freewheeling time parameter. The freewheeling time parameter includes a freewheeling time, a freewheeling time difference, and a freewheeling time rate of change. The preset electrical parameter thresholds corresponding to the freewheeling time, the freewheeling time difference, and the freewheeling time rate of change are a freewheeling time threshold, a freewheeling time difference threshold, and a freewheeling time rate of change threshold, respectively.

[0751] The freewheeling time can be directly tested by a timer. The timer is started at each phase change to calculate the freewheeling time. The freewheeling time can represent the load size, wherein the larger the load, the longer the freewheeling time.

[0752] The freewheeling time difference refers to the difference between the freewheeling time of the functional motor at two adjacent moments;

[0753] The freewheeling time change rate is used to characterize the changing trend of the freewheeling time of the functional motor 211 at the corresponding moment. The freewheeling time change rate may include the first-order derivative and the second-order derivative of the freewheeling time variation function. A freewheeling time variation curve can be obtained by fitting the freewheeling time determined by sampling at multiple moments, and the slope of the variation curve is used as the freewheeling time change rate. In fact, the slope of the variation curve is the first-order derivative of the freewheeling time. Alternatively, the slope of the freewheeling time variation curve is used as the freewheeling time change rate. In fact, the slope of the variation curve is the second-order derivative of the freewheeling time.

[0754] In some optional embodiments, the overload identification unit 221 determines whether the electrical parameter is greater than or equal to the corresponding preset electrical parameter threshold method, including: obtaining at least one continuous flow time parameter, and determining whether the at least one continuous flow time parameter is greater than or equal to the corresponding preset electrical parameter threshold.

[0755] In some optional embodiments, the overload identification unit 221 can also obtain multiple freewheeling time parameters, compare the multiple freewheeling time parameters with their corresponding preset freewheeling time parameter thresholds, and determine whether the multiple freewheeling time parameters are all greater than or equal to the corresponding preset freewheeling time parameter thresholds.

[0756] For example, the freewheeling time is compared with a corresponding preset freewheeling time threshold, and the freewheeling time difference is compared with a corresponding preset freewheeling time difference threshold. If the freewheeling time is greater than or equal to the preset freewheeling time threshold, and the freewheeling time difference is greater than or equal to the preset freewheeling time difference threshold, it is determined that the functional motor 211 enters the overload state.

[0757] For example, the freewheeling time, the freewheeling time difference, and the freewheeling time change rate are respectively compared with the corresponding preset freewheeling time threshold, preset freewheeling time difference threshold, and preset freewheeling time change rate threshold. If the three comparison results are all greater than or equal to the corresponding thresholds, it can be determined that the functional motor 211 has entered an overload state.

[0758] Taking the freewheeling time as an example, as shown in FIG34 , it is a schematic diagram of the freewheeling time of the functional motor 211 during operation. The freewheeling time of the functional motor 211 during commutation can represent the load size. The greater the load, the longer the freewheeling time, and vice versa. As shown in FIG34 , Δt1 and Δt2 represent the freewheeling time. The overload identification unit 221 compares the freewheeling time with the corresponding preset freewheeling time threshold. If the freewheeling time is greater than or equal to the freewheeling time threshold, it can be determined that the functional motor 211 has entered an overload state.

[0759] As shown in FIG35 , in an electric work vehicle provided in one or more optional embodiments of the present specification, the overload identification unit selects a target operating parameter from a plurality of operating parameters for monitoring, and determines whether the functional motor enters an overload state based on the target operating parameter and / or a change in the target operating parameter, including:

[0760] S601: Determine whether the power parameter matches the current first control strategy.

[0761] S602: In response to the power parameter not matching the first control strategy, the overload identification unit is configured to select the power parameter as the target operating parameter;

[0762] The control strategy that matches the power parameter is a power closed-loop control strategy. If the control strategy currently adopted by the controller component 22 for the functional motor 211 is a non-power closed-loop control strategy such as the speed closed-loop control strategy, the current closed-loop control strategy, the torque closed-loop control strategy, or the PWM duty cycle open-loop control strategy, the heavy load identification unit 221 may select the power parameter as the target operating parameter.

[0763] When selecting the target operating parameter, it is actually determined according to the current first control strategy. If the first control strategy is a non-power closed-loop control strategy, the overload identification unit 221 can select the power parameter as the target operating parameter.

[0764] S603: Determine whether the functional motor has entered an overload state based on the power parameter and / or the change in the power parameter. The overload identification unit 221 selects the power parameter as the target operating parameter and further monitors the power parameter. The change in the power parameter may include, for example, the difference between the power parameters at different times, the rate of increase or decrease of the power parameter, etc.

[0765] As shown in FIG36 , in an electric working vehicle provided in one or more optional embodiments of this specification, the method of the heavy load identification unit 221 determining whether the functional motor 211 enters a heavy load state based on the electrical parameters and / or changes in the electrical parameters includes:

[0766] S701: During the operation of the functional motor, determine whether the power parameter is greater than or equal to a corresponding preset power parameter threshold.

[0767] S702: In response to the power parameter being greater than or equal to the corresponding preset power parameter threshold, determining that the functional motor enters a heavy load state.

[0768] In some optional embodiments, the power parameters include motor power, motor power difference, and motor power change rate. The preset electrical parameter thresholds corresponding to the motor power, the motor power difference, and the motor power change rate are respectively a motor power threshold, a motor power difference threshold, and a motor power change rate threshold.

[0769] The heavy load identification unit 221 can calculate and determine the motor power of the functional motor 211 according to the bus voltage and bus current outputted at the DC side corresponding to the functional motor 211 .

[0770] The motor power difference refers to the difference in motor power of the functional motor at two adjacent moments.

[0771] The motor power change rate is used to characterize the changing trend of the motor power of the functional motor 211 at a corresponding moment. The motor power change rate may include the first-order derivative and the second-order derivative of the function of the motor power changing over time. A motor power change curve can be obtained by fitting the motor power determined by sampling at multiple moments, and the slope of the change curve is used as the motor power change rate. In fact, the slope of the change curve is the first-order derivative of the motor power. Alternatively, the slope of the motor power change curve is used as the motor power change rate. In fact, the slope of the change curve is the second-order derivative of the motor power.

[0772] The overload identification unit 221 determines whether the electrical parameter is greater than or equal to the corresponding preset electrical parameter threshold method, including: obtaining at least one power parameter, and determining whether the at least one power parameter is greater than or equal to the corresponding preset power parameter threshold.

[0773] In some optional embodiments, the overload identification unit 221 can also obtain multiple power parameters, compare the multiple power parameters with their corresponding preset power parameter thresholds, and determine whether the multiple power parameters are all greater than or equal to the corresponding preset power parameter thresholds.

[0774] For example, the motor power is compared with a corresponding preset motor power threshold, and the motor power difference is compared with a corresponding preset motor power difference threshold. If the motor power is greater than or equal to the preset motor power threshold, and the motor power difference is greater than or equal to the preset motor power difference threshold, it is determined that the functional motor 211 enters the overload state.

[0775] For example, the motor power, the motor power difference, and the motor power change rate are respectively compared with the corresponding preset motor power threshold, preset motor power difference threshold, and preset motor power change rate threshold. If the three comparison results are all greater than or equal to the corresponding thresholds, it can be determined that the functional motor 211 has entered an overload state.

[0776] As shown in FIG37 , in an electric work vehicle provided by one or more optional embodiments of the present specification, the overload identification unit selects a target operating parameter from the plurality of operating parameters for monitoring, and determines whether the functional motor enters an overload state based on the target operating parameter and / or a change in the target operating parameter, including:

[0777] S801: Determine whether the torque parameter matches the current first control strategy.

[0778] S802: In response to the torque parameter not matching the first control strategy, the overload identification unit is configured to select the torque parameter as the target operating parameter.

[0779] The control strategy that matches the torque parameter is a torque closed-loop control strategy. If the control strategy currently adopted by the controller component 22 for the functional motor 211 is a non-torque closed-loop control strategy such as the speed closed-loop control strategy, the power closed-loop control strategy, the current closed-loop control strategy, or the PWM duty cycle open-loop control strategy, the heavy load identification unit 221 may select the torque parameter as the target operating parameter.

[0780] When selecting the target operating parameter, it is actually determined based on the current first control strategy. If the first control strategy is a non-torque closed-loop control strategy, the heavy load identification unit 221 can select the torque parameter as the target operating parameter.

[0781] S803: Determine whether the functional motor has entered an overload state based on the torque parameter and / or the change in the torque parameter. The overload identification unit 221 selects the torque parameter as the target operating parameter and further monitors the torque parameter. The change in the torque parameter may include, for example, a difference between the torque parameters at different times, an increase or decrease rate of the torque parameter, etc.

[0782] As shown in FIG38 , in an electric working vehicle provided in one or more optional embodiments of this specification, the method in which the heavy load identification unit 221 determines whether the functional motor 211 enters a heavy load state based on the torque parameter and / or the change in the torque parameter includes:

[0783] S901: During the operation of the functional motor, determine whether the torque parameter is greater than or equal to a corresponding preset torque parameter threshold.

[0784] S902: In response to the torque parameter being greater than or equal to the corresponding preset torque parameter threshold, determining that the functional motor enters a heavy load state.

[0785] In some optional embodiments, the torque parameters include motor torque, motor torque difference, and motor torque change rate. The preset torque parameter thresholds corresponding to the motor torque, the motor torque difference, and the motor torque change rate are respectively a motor torque threshold, a motor torque difference threshold, and a motor torque change rate threshold.

[0786] The motor torque difference refers to the difference between the motor torques of the functional motor at two adjacent moments.

[0787] The motor torque change rate is used to characterize the change trend of the motor torque of the functional motor 211 at a corresponding moment. The motor torque change rate may include the first-order derivative and the second-order derivative of the function of the motor torque changing over time. A motor torque change curve can be obtained by fitting the motor torque determined by sampling at multiple moments, and the slope of the change curve is used as the motor torque change rate. In fact, the slope of the change curve is the first-order derivative of the motor torque. Alternatively, the slope of the motor torque change curve is used as the motor torque change rate. In fact, the slope of the change curve is the second-order derivative of the motor torque.

[0788] The overload identification unit 221 determines whether the torque parameter is greater than or equal to the corresponding preset torque parameter threshold method, including: obtaining at least one motor torque parameter, and determining whether the at least one motor torque parameter is greater than or equal to the corresponding preset torque parameter threshold.

[0789] In some optional embodiments, the overload identification unit 221 can also obtain multiple torque parameters, compare the multiple torque parameters with their corresponding preset torque parameter thresholds, and determine whether the multiple torque parameters are all greater than or equal to the corresponding preset torque parameter thresholds.

[0790] For example, the motor torque is compared with a corresponding preset motor torque threshold, and the motor torque difference is compared with a corresponding preset motor torque difference threshold. If the motor torque is greater than or equal to the preset motor torque threshold, and the motor torque difference is greater than or equal to the preset motor torque difference threshold, it is determined that the functional motor 211 has entered the overload state.

[0791] For example, the motor torque, the motor torque difference, and the motor torque change rate are respectively compared with the corresponding preset motor torque threshold, preset motor torque difference threshold, and preset motor torque change rate threshold. If the three comparison results are all greater than or equal to the corresponding thresholds, it can be determined that the functional motor 211 has entered an overload state.

[0792] As shown in FIG39 , in an electric work vehicle provided in one or more optional embodiments of the present specification, the overload identification unit selects a target operating parameter from the plurality of operating parameters for monitoring, and determines whether the functional motor enters an overload state based on the target operating parameter and / or a change in the target operating parameter, including:

[0793] S1001: Determine whether the PWM duty cycle parameter matches the current first control strategy.

[0794] S1002: In response to the PWM duty cycle parameter not matching the first control strategy, the overload identification unit is configured to select the PWM duty cycle parameter as the target operating parameter;

[0795] The control strategy that matches the PWM duty cycle parameter is a PWM duty cycle open-loop control strategy. If the control strategy currently adopted by the controller component 22 for the functional motor 211 is a non-PWM duty cycle open-loop control strategy such as the speed closed-loop control strategy, the current closed-loop control strategy, the torque closed-loop control strategy, or the power closed-loop control strategy, the heavy load identification unit 221 may select the PWM duty cycle parameter as the target operating parameter.

[0796] When selecting the target operating parameter, it is actually determined based on the current first control strategy. If the first control strategy is a non-PWM duty cycle open-loop control strategy, the overload identification unit 221 can select the PWM duty cycle parameter as the target operating parameter.

[0797] S1003: Determine whether the functional motor has entered an overload state based on the PWM duty cycle parameter and / or changes in the PWM duty cycle parameter. The overload identification unit 221 selects the PWM duty cycle parameter as the target operating parameter and further monitors the PWM duty cycle parameter. Changes in the PWM duty cycle parameter may include, for example, differences in the PWM duty cycle parameter at different times, and the rate of increase or decrease of the PWM duty cycle parameter.

[0798] As shown in FIG40 , in an electric working vehicle provided in one or more optional embodiments of this specification, the method of the overload identification unit 221 determining whether the functional motor 211 enters an overload state based on the electrical parameters and / or changes in the electrical parameters includes:

[0799] S1101: During the operation of the functional motor, determine whether the PWM duty cycle parameter is greater than or equal to a corresponding preset PWM duty cycle parameter threshold.

[0800] S1102: In response to the PWM duty cycle parameter being greater than or equal to the corresponding preset PWM duty cycle parameter threshold, determining that the functional motor enters a heavy load state.

[0801] In some optional embodiments, the PWM duty cycle parameters include the duty cycle, duty cycle difference, and duty cycle change rate of the control signal corresponding to the functional motor. The preset duty cycle parameter thresholds corresponding to the duty cycle, the duty cycle difference, and the duty cycle change rate are, respectively, a duty cycle threshold, an electric control ratio difference threshold, and a duty cycle change rate threshold.

[0802] The duty cycle refers to the duty cycle of the PWM control signal for the functional motor 211 .

[0803] The duty cycle difference refers to the difference between the duty cycles of the functional motor 211 at two adjacent moments.

[0804] The duty cycle change rate is used to characterize the changing trend of the duty cycle of the functional motor 211 at a given moment. The duty cycle change rate may include the first-order derivative and the second-order derivative of the duty cycle time-varying function. A duty cycle change curve can be obtained by fitting the duty cycles sampled at multiple moments. The slope of this change curve is used as the duty cycle change rate. In fact, the slope of this change curve is the first-order derivative of the duty cycle. Alternatively, the slope of the duty cycle change curve can be used as the duty cycle change rate. In fact, the slope of the change curve is the second-order derivative of the duty cycle.

[0805] The overload identification unit 221 determines whether the PWM duty cycle parameter is greater than or equal to the corresponding preset duty cycle parameter threshold value, including: obtaining at least one PWM duty cycle parameter, and determining whether the at least one PWM duty cycle parameter is greater than or equal to the corresponding preset duty cycle parameter threshold value.

[0806] In some optional embodiments, the overload identification unit 221 can also obtain multiple PWM duty cycle parameters, compare the multiple PWM duty cycle parameters with their corresponding preset duty cycle parameter thresholds, and determine whether the multiple PWM duty cycle parameters are all greater than or equal to the corresponding preset duty cycle parameter thresholds.

[0807] For example, the duty cycle is compared with a corresponding preset duty cycle threshold, and the duty cycle difference is compared with a corresponding preset duty cycle difference threshold. If the duty cycle is greater than or equal to the preset duty cycle threshold, and the duty cycle difference is greater than or equal to the preset duty cycle difference threshold, it is determined that the functional motor 211 enters the overload state.

[0808] For example, the duty cycle, the duty cycle difference, and the duty cycle change rate are respectively compared with the corresponding preset duty cycle threshold, preset duty cycle difference threshold, and preset duty cycle change rate threshold. If the three comparison results are all greater than or equal to the corresponding thresholds, it can be determined that the functional motor 211 enters the overload state.

[0809] In the above-described embodiment, the overload identification unit 221 selects one of multiple operating parameters as a target operating parameter and determines whether the functional motor 211 has entered an overload state based on the target operating parameter and / or changes in the target operating parameter. Alternatively, the overload identification unit 221 may select multiple operating parameters that do not match the current first control strategy as target operating parameters and determine whether the functional motor 211 has entered an overload state based on a ratio of the selected multiple operating parameters and changes in the ratio.

[0810] As shown in FIG41 , in an electric work vehicle provided in one or more optional embodiments of the present specification, the overload identification unit selects a target operating parameter from the plurality of operating parameters for monitoring, and determines whether the functional motor enters an overload state based on the target operating parameter and / or a change in the target operating parameter, including:

[0811] S1201: Determine whether the speed parameter and the electrical parameter match the current first control strategy.

[0812] S1202: In response to the speed parameter and the electrical parameter not matching the first control strategy, the overload identification unit is configured to select the speed parameter and the electrical parameter as the target operating parameter;

[0813] When selecting the target operating parameters, it is determined according to the current first control strategy. If the first control strategy is a non-speed closed-loop control strategy or a non-current closed-loop control strategy, the overload identification unit 221 can select the speed parameters and the electrical parameters as the target operating parameters.

[0814] S1203: Determine a flow ratio parameter according to the ratio of the speed parameter and the electrical parameter, and determine whether the functional motor enters a heavy load state according to the flow ratio parameter and / or a change in the flow ratio parameter.

[0815] The change of the flow ratio parameter may include, for example, the difference between the ratio of the speed parameter and the electrical parameter at different times, the rate of increase or decrease, etc.

[0816] In some optional embodiments, the flow ratio parameter includes a flow ratio, a flow ratio difference, and a flow ratio change rate. The preset flow ratio parameter thresholds corresponding to the flow ratio, the flow ratio difference, and the flow ratio change rate are a flow ratio threshold, an electric control ratio difference threshold, and a flow ratio change rate threshold, respectively.

[0817] The flow ratio refers to the ratio of the electrical parameter to the speed parameter. The electrical parameter may include the bus current parameter, the phase current parameter, the bus voltage parameter, the conduction phase voltage parameter, and the freewheeling time parameter. The speed parameter may include the motor speed parameter and the motor sector time parameter.

[0818] The turnover ratio difference refers to the difference between the turnover ratios at two adjacent moments.

[0819] The turnover ratio change rate is used to characterize the changing trend of the turnover ratio at a corresponding moment. The turnover ratio change rate may include the first-order derivative and second-order derivative of the turnover ratio time-varying function. A turnover ratio change curve can be obtained by fitting the turnover ratios determined by sampling at multiple moments, and the slope of this change curve is used as the turnover ratio change rate. In fact, the slope of this change curve is the first-order derivative of the turnover ratio. Alternatively, the slope of the turnover ratio change curve can be used as the turnover ratio change rate. In fact, the slope of the change curve is the second-order derivative of the turnover ratio.

[0820] In some optional embodiments, the ratio of the speed parameter to the electrical parameter is determined as the flow ratio parameter. Those skilled in the art will appreciate that the ratio of the electrical parameter to the speed parameter may also be used as the flow ratio parameter.

[0821] As shown in FIG42 , in an electric working vehicle provided by one or more optional embodiments of the present specification, in the case where the speed parameter is the motor speed parameter, the method of the overload identification unit 221 determining whether the functional motor 211 enters an overload state according to the flow ratio parameter and / or a change in the flow ratio parameter includes:

[0822] S1301: During the operation of the functional motor, determine whether the flow ratio parameter is greater than or equal to a corresponding preset flow ratio parameter threshold.

[0823] S1302: In response to the flow ratio parameter being greater than or equal to the corresponding preset flow ratio parameter threshold, determining that the functional motor enters a heavy load state.

[0824] In some optional embodiments, the ratio of the speed parameter to the electrical parameter is determined as the flow ratio parameter. Those skilled in the art will appreciate that the ratio of the electrical parameter to the speed parameter may also be used as the flow ratio parameter.

[0825] The overload identification unit 221 determines whether the turnover ratio parameter is greater than or equal to the corresponding preset turnover ratio parameter threshold method, including: obtaining at least one turnover ratio parameter, and determining whether the at least one turnover ratio parameter is greater than or equal to the corresponding preset turnover ratio parameter threshold.

[0826] Figure 43 shows a schematic diagram of determining a sudden overload condition based on a transfer ratio threshold during operation of the functional motor 211. Taking the motor speed as the speed parameter and the bus current as the electrical parameter as an example, the transfer ratio is determined based on the ratio of the two. Specifically, if the ratio of the bus current to the motor speed is used as the transfer ratio, and the transfer ratio is greater than or equal to the corresponding transfer ratio threshold, the functional motor 211 is determined to be in an overload state. If the ratio of the motor speed to the bus current is used as the transfer ratio, and the transfer ratio is less than or equal to the corresponding transfer ratio threshold, the functional motor 211 is determined to be in an overload state.

[0827] In some optional embodiments, the overload identification unit 221 can also obtain multiple turnover ratio parameters, compare the multiple turnover ratio parameters with their corresponding preset turnover ratio parameter thresholds, and determine whether the multiple turnover ratio parameters are all greater than or equal to the corresponding preset turnover ratio parameter thresholds.

[0828] For example, the flow ratio is compared with a corresponding preset flow ratio threshold, and the flow ratio difference is compared with a corresponding preset flow ratio difference threshold. If the flow ratio is greater than or equal to the preset flow ratio threshold, and the flow ratio difference is greater than or equal to the preset flow ratio difference threshold, it is determined that the functional motor 211 has entered the overload state.

[0829] For example, the flow ratio, the flow ratio difference, and the flow ratio change rate are respectively compared with the corresponding preset flow ratio threshold, the preset flow ratio difference threshold, and the preset flow ratio change rate threshold. If the three comparison results are all greater than or equal to the corresponding thresholds, it can be determined that the functional motor 211 has entered an overload state.

[0830] As shown in FIG44 , in an electric working vehicle provided by one or more optional embodiments of the present specification, in the case where the motor sector time parameter is selected as the speed parameter, the method of the overload identification unit 221 determining whether the functional motor 211 enters an overload state according to the flow ratio parameter and / or a change in the flow ratio parameter includes:

[0831] S1401: During the operation of the functional motor, determine whether the flow ratio parameter is less than or equal to a corresponding preset flow ratio parameter threshold.

[0832] S1402: In response to the flow ratio parameter being less than or equal to the corresponding preset flow ratio parameter threshold, determining that the functional motor enters a heavy load state.

[0833] Correspondingly, the overload identification unit 221 determines whether the turnover ratio parameter is less than or equal to the corresponding preset turnover ratio parameter threshold method, including: obtaining at least one turnover ratio parameter, and determining whether the at least one turnover ratio parameter is less than or equal to the corresponding preset turnover ratio parameter threshold.

[0834] FIG45 is another schematic diagram illustrating how the functional motor 211 determines a sudden overload change based on a flow ratio threshold value during operation. For example, the motor sector time is selected as the speed parameter, and the bus current is selected as the electrical parameter. The flow ratio is determined based on the ratio of the two.

[0835] The following describes an example method for determining a sudden overload change, using the ratios of bus current to motor speed, and motor speed to bus current, as examples. The same approach applies when using the ratios of bus current to motor sector time, and motor sector time to current, as the ratios.

[0836] The overload identification unit 221 can determine the current ratio (current to speed ratio or speed to current ratio) R k Is it greater than or equal to (the ratio of current to speed) or less than or equal to (the ratio of speed to current) a preset ratio threshold R? T If so, it is determined that the load has entered the heavy load operation area.

[0837] Furthermore, a time constraint condition can be added. Within a preset ΔT time (for example, 0.01 to 10 seconds), the current ratio (current to speed ratio or speed to current ratio) R k Greater than or equal to (ratio of current to speed) or less than or equal to (ratio of speed to current) the preset ratio threshold R T , it is determined that the load has entered the heavy load operation area.

[0838] Furthermore, the time limit added above can be segmented, with X ΔTs preset. x Time, for example, set X = 4, ΔT0 = 10 seconds, ΔT1 = 1 second, ΔT2 = 0.1 seconds, ΔT3 = 0.01 seconds, within ΔT0 (10 seconds) the current ratio (current to speed ratio or speed to current ratio) R k Greater than or equal to (ratio of current to speed) or less than or equal to (ratio of speed to current) R T0 , and / or the current ratio (current to speed ratio or speed to current ratio) R within ΔT1 (1 second) k Greater than or equal to (ratio of current to speed) or less than or equal to (ratio of speed to current) R T1 , and / or the current ratio (current to speed ratio or speed to current ratio) R within ΔT2 (0.1 seconds) kGreater than or equal to (ratio of current to speed) or less than or equal to (ratio of speed to current) R T2 , and / or the current ratio (current to speed ratio or speed to current ratio) R within ΔT3 (0.01 seconds) k Greater than or equal to (ratio of current to speed) or less than or equal to (ratio of speed to current) R T3 , it is determined that the load has entered the heavy load operation area, R T0 ~R T3 Satisfying the relationship (13)R T0 ≥R T1 ≥R T2 ≥R T3 , or R T0 ≤R T1 ≤R T2 ≤R T3 .

[0839] The relationship between the ratio threshold for determining entering heavy load and the preset speed of each gear also includes the above-mentioned time conditions.

[0840] The preset turnover ratio threshold corresponding to the turnover ratio may be set as an absolute value or a proportional value.

[0841] For the case where the threshold is set to an absolute value, the following example is shown:

[0842] (1) The ratio thresholds of each gear are the same within the same time interval:

[0843] After adding the time restriction condition, the ratio thresholds at the same gear at different time intervals are shown in Table 44 below.

[0844] Table 44

[0845] (2) The ratio thresholds of different gears are different within the same time interval:

[0846] The positive correlation threshold increases. After adding the time restriction condition, the ratio thresholds at the same gear at different time intervals are shown in Table 45 below.

[0847] Table 45

[0848] Alternatively, the negative correlation threshold decreases. After adding the time restriction condition, the ratio thresholds at the same gear at different time intervals are shown in Table 46 below.

[0849] Table 46

[0850] When the threshold is set as a proportional value, the following example is shown:

[0851] (1) The ratio of each level is the same within the same time interval:

[0852] After adding the time restriction condition, the ratio thresholds at the same gear at different time intervals are shown in Table 47 below.

[0853] Table 47

[0854] (2) The ratios of different levels are different within the same time interval:

[0855] The positive correlation ratio increases. After adding the time restriction condition, the ratio thresholds at the same gear at different time intervals are shown in Table 48 below.

[0856] Table 48

[0857] Alternatively, the negative correlation ratio decreases. After adding the time restriction condition, the ratio thresholds for the same gear at different time intervals are shown in Table 49 below.

[0858] Table 49

[0859] FIG46 is a schematic diagram illustrating how the functional motor 211 is judged to have a sudden overload condition based on a flow ratio difference threshold during operation. The ratio of the bus current to the motor speed, or the ratio of the motor speed to the bus current, is used as the flow ratio. The flow ratio difference is compared with a corresponding preset flow ratio difference threshold to determine whether the functional motor 211 has entered an overload state.

[0860] Figure 47 is another schematic diagram illustrating how to determine a sudden overload condition based on a flow ratio difference threshold during operation of the functional motor 211. The ratio of bus current to motor sector time, or the ratio of motor sector time to bus current, is used as the flow ratio. By comparing the flow ratio difference with a corresponding preset flow ratio difference threshold, it is determined whether the functional motor 211 has entered an overload state.

[0861] The following uses the ratio of bus current to motor speed and the ratio of motor speed to bus current as examples for explanation.

[0862] The overload identification unit 221 can obtain the ratio (current to speed ratio or speed to current ratio) R k Ratio R obtained at the previous moment k-1 Take the difference to get ΔR k , if ΔR k Greater than or equal to the preset ratio difference threshold ΔR T , it is determined that the load has entered the heavy load operation area.

[0863] Furthermore, a time constraint condition can be added, that is, within a preset ΔT time (eg, 0.01 to 10 seconds), the current ratio difference ΔR k Ratio difference threshold ΔR T , it is determined that the load has entered the heavy load operation area.

[0864] Furthermore, the time limit added above can be segmented, with X ΔTs preset. x Time, for example, set X = 4, ΔT0 = 10 seconds, ΔT1 = 1 second, ΔT2 = 0.1 seconds, ΔT3 = 0.01 seconds, and the ratio R obtained at the current moment k Ratio R to the previous ΔT0 (10 seconds) g Take the difference to get ΔR kg , R k Ratio R to the previous ΔT1 (1 second) h Take the difference to get ΔR kh , R k Ratio R to the previous ΔT2 (0.1 second) i Take the difference to get ΔR ki , R k Ratio R to the previous ΔT3 (0.01 seconds) j Take the difference to get ΔR kj , if ΔR kg Greater than or equal to the preset ratio difference threshold ΔR T0 , and / or ΔR kh Greater than or equal to the preset ratio difference threshold ΔR T1 , and / or ΔR ki Greater than or equal to the preset ratio difference threshold ΔR T2 , and / or ΔR kj Greater than or equal to the preset ratio difference threshold ΔR T3 , it is determined that the load has entered the heavy load operation area, ΔR T0 ~ΔR T3 Satisfying the relationship (14) ΔR T0 ≥ΔR T1 ≥ΔR T2 ≥ΔR T3 .

[0865] The relationship between the ratio difference for entering heavy load and the preset ratio of each gear is determined. Similarly, the above time conditions are also included:

[0866] Similarly, the preset turnover ratio threshold corresponding to the turnover ratio can be set as an absolute value or a proportional value.

[0867] FIG48 is a schematic diagram illustrating how to determine a sudden overload condition based on a turnover ratio change rate threshold during operation of the functional motor 211. The ratio of bus current to motor speed, or the ratio of motor speed to bus current, is used as the turnover ratio. By comparing the turnover ratio change rate with a corresponding preset turnover ratio change rate threshold, it is determined whether the functional motor 211 has entered an overload state.

[0868] FIG49 is another schematic diagram illustrating how to determine a sudden overload condition based on a turnover ratio change rate threshold during operation of the functional motor 211. The ratio of bus current to motor sector time, or the ratio of motor sector time to bus current, is used as the turnover ratio. By comparing the turnover ratio change rate with a corresponding preset turnover ratio change rate threshold, it is determined whether the functional motor 211 has entered an overload state.

[0869] The following uses the ratio of bus current to motor speed and the ratio of motor speed to bus current as examples for explanation.

[0870] The overload identification unit 221 can obtain t0, t1, t2...t k The ratio of the time R0, R1, R2...R k , R0, R1, R2…R k Perform linear fitting to obtain the corresponding curve slope k, which is calculated as follows: k = (Eti–Et*Ei) / [Et 2 –(Et) 2 ].

[0871] Among them, Etr represents the mathematical expectation of the product of the sampling time t and the ratio, Et represents the mathematical expectation of the sampling time t, Er represents the mathematical expectation of the ratio, and Et 2 Represents the mathematical expectation of the square of the sampling time t, (Et) 2 Represents the square of the mathematical expectation of the sampling time t.

[0872] Assume that Δt0=t1-t0, Δt1=t2-t1, Δt k =t k +1-t k In order to facilitate software calculation, it is generally designed as Δt0=Δt1=……=Δt k Therefore, the above formula can be simplified as: k=[n*Σ(t*r)–Σt*Σr] / [n*Σt 2 –Σt*Σt], where n is a positive integer. In order to further simplify the calculation process and reduce software calculation overhead, n in the above simplified formula can be set to 2 m , m is a positive integer.

[0873] When the slope k is greater than or equal to (the ratio of current to speed, k in Figure 48IN ≥k INT ) or less than or equal to (the ratio of speed to current, k in Figure 48 NI ≤k NIT ) The preset slope threshold k T , which means that the load is determined to have entered the heavy load operation area.

[0874] Furthermore, in order to obtain a better judgment effect, a ratio filtering method can be added on the basis of the above. k is the value obtained after filtering. Thus, when the fixed window filter series method is used, Δt0, Δt1, Δt2…Δt k The value is X ratio sampling intervals. For example, when the ratio is obtained every 1ms, and X is preset to 8, the filtered value will be calculated every 8ms, Δt0 = Δt1 = Δt2 = Δt k =8ms; When the sliding window filter series method is used, the above preset conditions are still applied, then Δt0=Δt1=Δt2=Δt k =1ms. After each fixed window filtering or sliding window filtering is completed, the slope k is calculated using formula (15), which is the first-order derivative value of the ratio with respect to unit time.

[0875] Furthermore, if the ratio span of the motor operation is relatively large, Δt0, Δt1, Δt2…Δt k The value of can be adjusted dynamically according to the current motor ratio, because if Δt0, Δt1, Δt2…Δt k If it is too small, when the motor ratio is relatively low, the ratio sampling frequency is much higher than the motor ratio filtering frequency, and the ratio sampled at each moment may be the same, which wastes computing resources unnecessarily. Or, when the motor ratio fluctuates on a small time scale, it is easy to interfere with the calculation result and form a misjudgment. If Δt0, Δt1, Δt2…Δt k If it is too large, when the motor ratio is relatively high, the ratio sampling is far lower than the actual ratio change frequency, and the obtained data fluctuates greatly, or the actual ratio change rate may meet the application requirements, but the actual calculation judgment fails to recognize it. Therefore, Δt0, Δt1, Δt2…Δt k The adjustment rule is that when the ratio is high, the time interval is small, and when the ratio is low, the time interval is large. There are three ways to adjust this time interval. The first is to adjust the above 1ms ratio sampling interval, for example, to 0.5ms or 2ms. In this way, under the fixed window filter series method, Δt0 = Δt1 = Δt2 = Δt k =4ms or 16ms, under the sliding window filter series method, Δt0=Δt1=Δt2=Δt k=0.5ms or 2ms; the second is to adjust the window length (number of sampling points X), for example, to X=4 or X=16, so that under the fixed window filter series method Δt0=Δt1=Δt2=Δt k =4ms or 16ms, under the sliding window filter series method, Δt0=Δt1=Δt2=Δt k Still equal to 1ms; the third method is to adjust the ratio sampling interval and the window length (number of sampling points X) at the same time. In addition, since the ratio decreases rapidly when the load suddenly changes, this process will not adjust Δt0, Δt1, Δt2...Δt k , and adjustments will only be made after the ratio has stabilized for a period of time.

[0876] Furthermore, after each fixed window filtering or sliding window filtering, the slope is calculated using the above formula, so that a set of k0, k1, k2...k k , for k0, k1, k2…k k Then perform linear fitting to obtain the corresponding slope k', which is calculated as follows: k'=(Etk–Et*Ek) / [Et 2 –(Et) 2 ].

[0877] Among them, Etk is the mathematical expectation of the ratio slope at time t each time the ratio slope is obtained, Et is the mathematical expectation of the ratio slope at time t each time the ratio slope is obtained, Ek is the mathematical expectation of the ratio slope, Et 2 The mathematical expectation of the square of the time t at which the slope of the ratio is obtained each time, (Et) 2 The square of the mathematical expectation at sampling time t.

[0878] Since k0, k1, k2…k are obtained each time k The time intervals are equal, so Δt'0, Δt'1, Δt'2…Δt' k Therefore, the above formula can be simplified to: k'=[n'*Σ(t*k)–Σt*Σk] / [n'*Σt 2 –Σt*Σt], where n' is a positive integer. In order to further simplify the calculation process and reduce software calculation overhead, n' in the above simplified formula can be set to 2 m’ , m' is a positive integer. When the slope k' is greater than or equal to (the ratio of current to speed) or less than or equal to (the ratio of speed to current) the preset slope threshold k' T , which means the load has entered the heavy load operation area. Here, the slope k' is the second-order derivative of the ratio with respect to unit time.

[0879] As shown in FIG50 , in an electric work vehicle provided in one or more optional embodiments of the present specification, the overload identification unit selects a target operating parameter from the plurality of operating parameters for monitoring, and determines whether the functional motor enters an overload state based on the target operating parameter and / or a change in the target operating parameter, including:

[0880] S1501: Determine whether the speed parameter and the power parameter match the current first control strategy.

[0881] S1502: In response to the speed parameter and the power parameter not matching the first control strategy, the overload identification unit is configured to select the speed parameter and the power parameter as the target operating parameter;

[0882] When selecting the target operating parameters, it is determined according to the current first control strategy. If the first control strategy is neither a speed closed-loop control strategy nor a power closed-loop control strategy, the overload identification unit 221 can select the speed parameter and the power parameter as the target operating parameters.

[0883] S1503: Determine a power-to-conversion ratio parameter according to the ratio of the speed parameter to the power parameter, and determine whether the functional motor enters an overload state according to the power-to-conversion ratio parameter and / or a change in the power-to-conversion ratio parameter.

[0884] The change of the power-to-conversion ratio parameter may include, for example, the difference between the ratio of the speed parameter and the power parameter at different times, the rate of increase or decrease, etc.

[0885] In some optional embodiments, the power conversion ratio parameter includes a power conversion ratio, a power conversion ratio difference, and a power conversion ratio change rate. The preset power conversion ratio parameter thresholds corresponding to the power conversion ratio, the power conversion ratio difference, and the power conversion ratio change rate are a power conversion ratio threshold, an electric control ratio difference threshold, and a power conversion ratio change rate threshold, respectively.

[0886] The power-to-conversion ratio refers to the ratio of the power parameter to the speed parameter. The power parameter may include the motor power, motor speed difference, and motor power change rate. The speed parameter may include the motor speed parameter and the motor sector time parameter.

[0887] The power conversion ratio difference refers to the difference between the power conversion ratio at two adjacent moments.

[0888] The power conversion ratio change rate is used to characterize the changing trend of the power conversion ratio at a corresponding moment. The power conversion ratio change rate may include the first-order derivative and second-order derivative of the power conversion ratio time-varying function. A power conversion ratio change curve can be obtained by fitting the power conversion ratios sampled and determined at multiple moments. The slope of this change curve is used as the power conversion ratio change rate. In fact, the slope of this change curve is the first-order derivative of the ...

Claims

1. An electric working vehicle, characterized in that: include: Motor; A collection module, the collection module is used to collect at least one mechanical parameter and at least one electrical parameter of the motor, the mechanical parameter includes a speed parameter, a sector time parameter or a torque parameter, and the electrical parameter includes a bus current parameter, a phase current parameter, a bus voltage parameter, a power parameter, a freewheeling time parameter or a duty cycle parameter; A detection module, the detection module is used to process the mechanical parameters and electrical parameters of the motor according to a target calculation formula and generate a target value, the target calculation formula at least including a ratio, a slope of the ratio or a difference of the ratio; A judgment module, the judgment module is used to determine whether the motor is in an overload state according to the target value and the target preset threshold value. If the target value does not meet the target preset threshold value, it is determined that the motor is in an overload state, wherein the target preset threshold value corresponds to the target calculation formula.

2. The electric working vehicle according to claim 1, characterized in that: The speed parameters include: speed, speed difference or the slope of the speed curve, the sector time parameters include: sector time, sector time difference or the slope of the sector time curve, the torque parameters include: torque, torque difference or the slope of the torque curve, the bus current parameters include: bus current, bus current difference or the slope of the bus current curve, the phase current parameters include: phase current, phase current difference or the slope of the phase current curve, the bus voltage parameters include: bus voltage, bus voltage difference or the slope of the bus voltage curve, the power parameters include: power, power difference or the slope of the power curve, the freewheeling time parameters include: freewheeling time, freewheeling time difference or the slope of the freewheeling time curve, the duty cycle parameters include: duty cycle parameters, duty cycle parameter difference or the slope of the duty cycle parameter curve, and the target value is the ratio of the same type of the mechanical parameter to the electrical parameter.

3. The electric working vehicle according to claim 1, characterized in that: The target calculation formula includes: calculating the ratio of the mechanical parameters to the electrical parameters of the motor, or the ratio of different electrical parameters of the motor, and the target value is the ratio. The judgment module also includes: comparing the ratio with the target preset threshold, and if the ratio does not meet the target preset threshold, determining that the motor is in an overloaded state.

4. The electric working vehicle according to claim 1, characterized in that: The target calculation formula includes: calculating the ratio of the mechanical parameters to the electrical parameters of the motor, or the ratio of different electrical parameters of the motor, and calculating the ratio value of the ratio to the preset ratio, the target value is the ratio value, and the judgment module also includes: comparing the ratio value with the target preset threshold value, if the ratio value does not meet the target preset threshold value, determining that the motor is in the overload state.

5. The electric working vehicle according to claim 1, characterized in that: The target calculation formula includes: calculating the ratio of the mechanical parameters to the electrical parameters of the motor, or the ratio of different electrical parameters of the motor, and calculating the difference of the ratios within a preset time, and the target value is the difference. The judgment module also includes: comparing the difference with the target preset threshold, and if the difference does not meet the target preset threshold, determining that the motor is in the overload state.

6. The electric working vehicle according to claim 1, characterized in that: The target calculation formula includes: calculating the ratio of the mechanical parameters to the electrical parameters of the motor, or the ratio of different electrical parameters of the motor, and obtaining the slope of the curve of the ratio, the target value is the slope, and the judgment module also includes: comparing the slope with the target preset threshold, if the slope does not meet the target preset threshold, determining that the motor is in the overload state.

7. The electric working vehicle according to any one of claims 3 to 6, characterized in that: The motor includes: a first gear, a second gear and a third gear with output capacities increasing in sequence, and the target preset threshold is the same when the motor is in the first gear, the motor is in the second gear, and the motor is in the third gear, or the target preset threshold decreases in sequence when the motor is in the first gear, the motor is in the second gear, and the motor is in the third gear, or the target preset threshold increases in sequence when the motor is in the first gear, the motor is in the second gear, and the motor is in the third gear.

8. The electric working vehicle according to claim 7, characterized in that: The target preset threshold is determined according to the sampling time, and the shorter the sampling time interval is, the smaller the target preset threshold is. The sampling time interval is: the time interval for obtaining two adjacent mechanical parameters or obtaining two adjacent electrical parameters.

9. The electric working vehicle according to claim 1, characterized in that: Also includes: A control module is used to adjust the mechanical parameters or electrical parameters of the motor when the motor is in the overload state to reduce the working efficiency of the motor until the motor is out of the overload state.

10. A method for detecting a heavy load state, characterized in that: Applied to electric work vehicles, including: Collecting at least one mechanical parameter and at least one electrical parameter of the motor, the mechanical parameter including a speed parameter, a sector time parameter or a torque parameter, and the electrical parameter including a bus current parameter, a phase current parameter, a bus voltage parameter, a power parameter, a freewheeling time parameter or a duty cycle parameter; According to a target calculation formula, the mechanical parameters and electrical parameters of the motor are processed to generate a target value, wherein the target calculation formula at least includes a ratio, a slope of a ratio, or a difference of a ratio; Whether the motor is in an overload state is determined according to the target value and the target preset threshold value. If the target value does not meet the target preset threshold value, it is determined that the motor is in an overload state, wherein the target preset threshold value is correspondingly related to the target calculation formula.

11. An electric working vehicle, characterized in that: include: Frame; a functional mechanism, attached to the vehicle frame, comprising a functional motor and an output assembly driven by the functional motor to perform a specific functional operation; A controller component, used to control the operating state of the functional motor; The functional motor has a plurality of operating parameters, and the controller component has a plurality of control strategies corresponding to and matching the plurality of operating parameters for the functional motor; The controller assembly includes a heavy load identification unit and a heavy load control unit; The overload identification unit is configured to select a target operating parameter from the multiple operating parameters for monitoring, and determine whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter; wherein the target operating parameter does not match a first control strategy currently adopted by the controller component for the functional motor; In response to determining that the functional motor enters the overload state, the overload control unit is configured to select a second control strategy from the multiple control strategies, and control and adjust the functional motor based on the second control strategy to make it exit the overload state.

12. The electric working vehicle according to claim 11, characterized in that: The various operating parameters of the functional motor include speed parameters, electrical parameters, power parameters, torque parameters and PWM duty cycle parameters; The various control strategies corresponding to the various operating parameters are speed closed-loop control strategy, current closed-loop control strategy, power closed-loop control strategy, torque closed-loop control strategy and PWM duty cycle open-loop control strategy.

13. The electric working vehicle according to claim 12, characterized in that: The overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including: In response to the rotation speed parameter not matching the first control strategy, the heavy load identification unit is configured to select the rotation speed parameter as the target operating parameter; The overload identification unit is further configured to monitor the speed parameter, and determine whether the functional motor enters an overload state according to the speed parameter and / or a change in the speed parameter.

14. The electric working vehicle according to claim 13, characterized in that: The speed parameter includes a motor speed parameter; The overload identification unit monitors the speed parameter, and determines whether the functional motor enters an overload state according to the speed parameter and / or a change in the speed parameter, including: During the operation of the functional motor, determining whether the motor speed parameter is greater than or equal to a corresponding preset motor speed parameter threshold; In response to the motor speed parameter being greater than or equal to the corresponding preset motor speed parameter threshold, it is determined that the functional motor enters a heavy load state.

15. The electric working vehicle according to claim 14, characterized in that: The motor speed parameters include motor speed, motor speed difference and motor speed change rate; Wherein, the motor speed difference refers to the difference between the motor speeds of the functional motor at two adjacent moments; The motor speed change rate is used to characterize the change trend of the motor speed of the functional motor at a corresponding moment; The overload identification unit determines whether the motor speed parameter is greater than or equal to a corresponding preset motor speed parameter threshold value during the operation of the functional motor, including: At least one motor speed parameter is obtained, and it is determined whether the at least one motor speed parameter is less than or equal to a corresponding preset motor speed parameter threshold.

16. The electric working vehicle according to claim 13, characterized in that: The speed parameter includes a motor sector time parameter; the overload identification unit monitors the speed parameter, and determines whether the functional motor enters an overload state according to the speed parameter and / or a change in the speed parameter, including: During the operation of the functional motor, determining whether the motor sector time parameter is greater than or equal to a corresponding preset motor sector time parameter threshold; In response to the motor sector time parameter being greater than or equal to the corresponding preset motor sector time parameter threshold, it is determined that the functional motor enters a heavy load state.

17. The electric working vehicle according to claim 16, characterized in that: The motor sector time parameters include motor sector time, motor sector time difference and motor sector time change rate; The electrical cycle of the functional motor includes a plurality of sectors, and the motor sector time refers to the corresponding duration of each sector; The motor sector time difference refers to the difference between two adjacent moments corresponding to the motor sector time; The motor sector time change rate is used to characterize the change trend of the motor sector time; The overload identification unit determines whether the motor sector time parameter is greater than or equal to a corresponding preset motor sector time parameter threshold value during the operation of the functional motor, including: At least one motor sector time parameter is obtained, and it is determined whether the at least one motor sector time parameter is greater than or equal to a corresponding preset motor sector time parameter threshold.

18. The electric working vehicle according to claim 12, characterized in that: The overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including: In response to the electrical parameter not matching the first control strategy, the heavy load identification unit is configured to select the electrical parameter as the target operating parameter; The overload identification unit is further configured to monitor the electrical parameters and determine whether the functional motor enters an overload state according to the electrical parameters and / or changes in the electrical parameters.

19. The electric working vehicle according to claim 18, characterized in that: The overload identification unit monitors the electrical parameters, and determines whether the functional motor enters an overload state according to the electrical parameters and / or changes in the electrical parameters, including: During the operation of the functional motor, determining whether the electrical parameter is greater than or equal to a corresponding preset electrical parameter threshold; In response to the electrical parameter being greater than or equal to the corresponding preset electrical parameter threshold, it is determined that the functional motor enters a heavy load state.

20. The electric working vehicle according to claim 19, characterized in that: The electrical parameters include bus current parameters; The bus current parameters include bus current, bus current difference and bus current change rate; The bus current difference refers to the difference between the bus currents of the functional motor at two adjacent moments; The bus current change rate is used to characterize the change trend of the bus current of the functional motor at a corresponding moment; The overload identification unit determines whether the electrical parameter is greater than or equal to the corresponding preset electrical parameter threshold value during the operation of the functional motor, including: At least one bus current parameter is obtained, and it is determined whether the at least one bus current parameter is greater than or equal to the corresponding preset electrical parameter threshold.

21. The electric working vehicle according to claim 19, characterized in that: The electrical parameters include phase current parameters; The phase current parameters include phase current, phase current difference and phase current change rate; The phase current difference refers to the difference between the phase currents of the functional motor at two adjacent moments; The phase current change rate is used to characterize the change trend of the phase current of the functional motor at a corresponding moment; The overload identification unit determines whether the electrical parameter is greater than or equal to the corresponding preset electrical parameter threshold value during the operation of the functional motor, including: At least one phase current parameter is obtained, and it is determined whether the at least one phase current parameter is greater than or equal to the corresponding preset electrical parameter threshold.

22. The electric working vehicle according to claim 19, characterized in that: The electrical parameters include bus voltage parameters; The bus voltage parameters include bus voltage drop, bus voltage drop difference and bus voltage drop change rate; The bus voltage drop refers to the decrease in the bus voltage during the operation of the functional motor compared to the bus voltage before the motor starts to work; The bus voltage drop difference refers to the difference in bus voltage drop of the functional motor at two adjacent moments; The bus voltage drop change rate is used to characterize the change trend of the bus voltage drop of the functional motor at a corresponding moment; The overload identification unit determines whether the electrical parameter is greater than or equal to the corresponding preset electrical parameter threshold value during the operation of the functional motor, including: Acquire at least one bus voltage parameter, and determine whether the at least one bus voltage parameter is greater than or equal to the corresponding preset electrical parameter threshold.

23. The electric working vehicle according to claim 19, characterized in that: The electrical parameters include conduction phase voltage parameters; The conduction phase voltage parameters include conduction phase voltage drop, conduction phase voltage drop difference and conduction phase voltage drop change rate; The conduction phase voltage drop refers to the relative value of the conduction phase voltage change of the functional motor in one commutation cycle; The conduction phase voltage drop difference refers to the difference in conduction phase voltage drops corresponding to different commutation cycles of the functional motor; The conduction phase voltage drop change rate is used to characterize the change trend of the conduction phase voltage drop of the functional motor; The overload identification unit determines whether the electrical parameter is greater than or equal to the corresponding preset electrical parameter threshold value during the operation of the functional motor, including: Acquire at least one conduction phase voltage parameter, and determine whether the at least one conduction phase voltage parameter is greater than or equal to the corresponding preset electrical parameter threshold.

24. The electric working vehicle according to claim 19, characterized in that: The electrical parameters include a freewheeling time parameter; The freewheeling time parameters include the freewheeling time, the freewheeling time difference and the freewheeling time change rate when the functional motor is commutated; The freewheeling time difference refers to the difference in freewheeling time corresponding to different commutation cycles of the functional motor; The freewheeling time change rate is used to characterize the change trend of the freewheeling time of the functional motor; The overload identification unit determines whether the electrical parameter is greater than or equal to the corresponding preset electrical parameter threshold value during the operation of the functional motor, including: At least one freewheeling time parameter is obtained, and it is determined whether the at least one freewheeling time parameter is greater than or equal to the corresponding preset electrical parameter threshold.

25. The electric working vehicle according to claim 12, characterized in that: The overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including: In response to the power parameter not matching the first control strategy, the overload identification unit is configured to select the power parameter as the target operating parameter; The overload identification unit is further configured to monitor the power parameter, and determine whether the functional motor enters an overload state according to the power parameter and / or a change in the power parameter.

26. The electric working vehicle according to claim 25, characterized in that: The overload identification unit monitors the power parameter, and determines whether the functional motor enters an overload state according to the power parameter and / or a change in the power parameter, including: During the operation of the functional motor, determining whether the power parameter is greater than or equal to a corresponding preset power parameter threshold; In response to the power parameter being greater than or equal to the corresponding preset power parameter threshold, it is determined that the functional motor enters a heavy load state.

27. The electric working vehicle according to claim 26, characterized in that: The power parameters include motor power, motor power difference and motor power change rate; Wherein, the motor power difference refers to the difference between the motor power of the functional motor at two adjacent moments; The motor power change rate is used to characterize the change trend of the motor power of the functional motor at a corresponding moment; The overload identification unit determines whether the power parameter is greater than or equal to a corresponding preset motor power parameter threshold value during the operation of the functional motor, including: Acquire at least one power parameter, and determine whether the at least one power parameter is greater than or equal to a corresponding preset power parameter threshold.

28. The electric working vehicle according to claim 12, characterized in that: The overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including: In response to the torque parameter not matching the first control strategy, the heavy load identification unit is configured to select the torque parameter as the target operating parameter; The overload identification unit is further configured to monitor the torque parameter, and determine whether the functional motor enters an overload state according to the torque parameter and / or a change in the torque parameter.

29. The electric working vehicle according to claim 28, characterized in that: The overload identification unit monitors the torque parameter, and determines whether the functional motor enters an overload state according to the torque parameter and / or a change in the torque parameter, including: During the operation of the functional motor, determining whether the torque parameter is greater than or equal to a corresponding preset torque parameter threshold; In response to the torque parameter being greater than or equal to the corresponding preset torque parameter threshold, it is determined that the functional motor enters a heavy load state.

30. The electric working vehicle according to claim 29, characterized in that: The torque parameters include motor torque, motor torque difference and motor torque change rate; Wherein, the motor torque difference refers to the difference between the motor torque of the functional motor at two adjacent moments; The motor torque change rate is used to characterize the change trend of the motor torque of the functional motor at a corresponding moment; The overload identification unit determines whether the torque parameter is greater than or equal to a corresponding preset torque parameter threshold value during the operation of the functional motor, including: At least one torque parameter is obtained, and it is determined whether the at least one torque parameter is greater than or equal to a corresponding preset torque parameter threshold.

31. The electric working vehicle according to claim 12, characterized in that: The overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including: In response to the PWM duty cycle parameter not matching the first control strategy, the overload identification unit is configured to select the PWM duty cycle parameter as the target operating parameter; The overload identification unit is further configured to monitor the PWM duty cycle parameter, and determine whether the functional motor enters an overload state according to the PWM duty cycle parameter and / or a change in the PWM duty cycle parameter.

32. The electric working vehicle according to claim 31, characterized in that: The overload identification unit monitors the PWM duty cycle parameter, and determines whether the functional motor enters an overload state according to the PWM duty cycle parameter and / or a change in the PWM duty cycle parameter, including: During the operation of the functional motor, determining whether the PWM duty cycle parameter is greater than or equal to a corresponding preset duty cycle parameter threshold; In response to the PWM duty cycle parameter being greater than or equal to the corresponding preset duty cycle parameter threshold, it is determined that the functional motor enters a heavy load state.

33. The electric working vehicle according to claim 32, characterized in that: The PWM duty cycle parameters include the duty cycle, duty cycle difference and duty cycle change rate of the corresponding control signal of the functional motor; Wherein, the duty cycle difference refers to the difference between the duty cycles of the functional motor at two adjacent moments; The duty cycle change rate is used to characterize the change trend of the duty cycle of the functional motor at a corresponding moment; The overload identification unit determines whether the duty cycle parameter is greater than or equal to a corresponding preset duty cycle parameter threshold value during the operation of the functional motor, including: At least one PWM duty cycle parameter is obtained, and it is determined whether the at least one PWM duty cycle parameter is greater than or equal to a corresponding preset duty cycle parameter threshold.

34. The electric working vehicle according to claim 12, characterized in that: The overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including: In response to the rotation speed parameter and the electrical parameter not matching the first control strategy, the overload identification unit is configured to select the rotation speed parameter and the electrical parameter as the target operating parameter; The overload identification unit is also configured to monitor the speed parameter and the electrical parameter, determine the flow ratio parameter according to the ratio of the electrical parameter to the speed parameter, and determine whether the functional motor enters an overload state according to the flow ratio parameter and / or changes in the flow ratio parameter.

35. The electric working vehicle according to claim 34, characterized in that: The speed parameter includes a motor speed parameter, and the flow ratio parameter represents a ratio of the electrical parameter to the motor speed parameter; The overload identification unit determines whether the functional motor enters an overload state according to the flow ratio parameter and / or a change in the flow ratio parameter, including: During the operation of the functional motor, determining whether the flow ratio parameter is greater than or equal to a corresponding preset flow ratio parameter threshold; In response to the flow ratio parameter being greater than or equal to the corresponding preset flow ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

36. The electric working vehicle according to claim 34, characterized in that: The speed parameter includes a motor sector time parameter, and the flow ratio parameter represents a ratio of the electrical parameter to the motor sector time parameter; The overload identification unit determines whether the functional motor enters an overload state according to the flow ratio parameter and / or the change of the flow ratio parameter, including: During the operation of the functional motor, determining whether the flow ratio parameter is less than or equal to a corresponding preset flow ratio parameter threshold; In response to the flow ratio parameter being less than or equal to the corresponding preset flow ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

37. The electric working vehicle according to claim 35 or 36, characterized in that: The circulation ratio parameters include circulation ratio, circulation ratio difference and circulation ratio change rate; Wherein, the flow ratio refers to the ratio of the electrical parameter to the speed parameter; The turnover ratio difference refers to the difference between the turnover ratios at two adjacent moments; The turnover ratio change rate is used to characterize the change trend of the turnover ratio at a corresponding moment; The overload identification unit determines whether the flow ratio parameter is greater than or equal to the corresponding preset flow ratio parameter threshold during the operation of the functional motor, including: Obtain at least one turnover ratio parameter, and determine whether the at least one turnover ratio parameter is greater than or equal to a corresponding preset turnover ratio parameter threshold.

38. The electric working vehicle according to claim 12, characterized in that: The overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including: In response to the rotation speed parameter and the power parameter not matching the first control strategy, the overload identification unit is configured to select the rotation speed parameter and the power parameter as the target operating parameter; The overload identification unit is also configured to monitor the speed parameter and the power parameter, determine the power-to-speed ratio parameter according to the ratio of the power parameter to the speed parameter, and determine whether the functional motor enters an overload state according to the power-to-speed ratio parameter and / or changes in the power-to-speed ratio parameter.

39. The electric working vehicle according to claim 38, characterized in that: The speed parameter includes a motor speed parameter, and the power-to-power ratio parameter represents a ratio of the power parameter to the motor speed parameter; The overload identification unit determines whether the functional motor enters an overload state according to the power-to-conversion ratio parameter and / or a change in the power-to-conversion ratio parameter, including: During the operation of the functional motor, determining whether the power-to-conversion ratio parameter is greater than or equal to a corresponding preset power-to-conversion ratio parameter threshold; In response to the power-to-conversion ratio parameter being greater than or equal to the corresponding preset power-to-conversion ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

40. The electric working vehicle according to claim 38, characterized in that: The speed parameter includes a motor sector time parameter, and the power-to-conversion ratio parameter represents a ratio of the power parameter to the motor sector time parameter; The overload identification unit determines whether the functional motor enters an overload state according to the power-to-conversion ratio parameter and / or a change in the power-to-conversion ratio parameter, including: During the operation of the functional motor, determining whether the power-to-conversion ratio parameter is less than or equal to a corresponding preset power-to-conversion ratio parameter threshold; In response to the power-to-conversion ratio parameter being less than or equal to the corresponding preset power-to-conversion ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

41. The electric working vehicle according to claim 39 or 40, characterized in that: The power conversion ratio parameters include power conversion ratio, power conversion ratio difference and power conversion ratio change rate; Wherein, the power-to-conversion ratio refers to the ratio of the power parameter to the speed parameter; The power-to-conversion ratio difference refers to the difference between the power-to-conversion ratio at two adjacent moments; The power-to-conversion ratio change rate is used to characterize the change trend of the power-to-conversion ratio at a corresponding moment; The overload identification unit determines whether the power-to-conversion ratio parameter is greater than or equal to the corresponding preset power-to-conversion ratio parameter threshold during the operation of the functional motor, including: At least one power-to-conversion ratio parameter is obtained, and it is determined whether the at least one power-to-conversion ratio parameter is greater than or equal to a corresponding preset power-to-conversion ratio parameter threshold.

42. The electric working vehicle according to claim 12, characterized in that: The overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including: In response to the rotation speed parameter and the torque parameter not matching the first control strategy, the overload identification unit is configured to select the rotation speed parameter and the torque parameter as the target operating parameter; The overload identification unit is also configured to monitor the speed parameter and the torque parameter, determine the torque-to-speed ratio parameter according to the ratio of the torque parameter to the speed parameter, and determine whether the functional motor enters an overload state according to the torque-to-speed ratio parameter and / or changes in the torque-to-speed ratio parameter.

43. The electric working vehicle according to claim 42, characterized in that: The speed parameter includes a motor speed parameter, and the torque-to-speed ratio parameter represents a ratio of the torque parameter to the motor speed parameter; The overload identification unit determines whether the functional motor enters an overload state according to the torque-to-turn ratio parameter and / or a change in the torque-to-turn ratio parameter, including: During the operation of the functional motor, determining whether the torque-to-turn ratio parameter is greater than or equal to a corresponding preset torque-to-turn ratio parameter threshold; In response to the torque-to-turn ratio parameter being greater than or equal to the corresponding preset torque-to-turn ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

44. The electric working vehicle according to claim 42, characterized in that: The speed parameter includes a motor sector time parameter, and the torque-to-speed ratio parameter represents a ratio of the torque parameter to the motor sector time parameter; The overload identification unit determines whether the functional motor enters an overload state according to the torque-to-turn ratio parameter and / or a change in the torque-to-turn ratio parameter, including: During the operation of the functional motor, determining whether the torque-to-turn ratio parameter is less than or equal to a corresponding preset torque-to-turn ratio parameter threshold; In response to the torque-to-turn ratio parameter being less than or equal to the corresponding preset torque-to-turn ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

45. The electric working vehicle according to claim 43 or 44, characterized in that: The torque-to-turn ratio parameters include the torque-to-turn ratio, the torque-to-turn ratio difference and the torque-to-turn ratio change rate; Wherein, the torque-to-speed ratio refers to the ratio of the torque parameter to the speed parameter; The torque-to-turn ratio difference refers to the difference between the torque-to-turn ratio at two adjacent moments; The torque-to-turn ratio change rate is used to characterize the change trend of the torque-to-turn ratio at a corresponding moment; The overload identification unit determines whether the torque-to-turn ratio parameter is greater than or equal to the corresponding preset torque-to-turn ratio parameter threshold during the operation of the functional motor, including: At least one torque-to-turnover ratio parameter is obtained, and it is determined whether the at least one torque-to-turnover ratio parameter is greater than or equal to a corresponding preset torque-to-turnover ratio parameter threshold.

46. ​​The electric working vehicle according to claim 12, characterized in that: The overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including: In response to the speed parameter and the PWM duty cycle parameter not matching the first control strategy, the overload identification unit is configured to select the speed parameter and the PWM duty cycle parameter as the target operating parameter; The overload identification unit is further configured to monitor the speed parameter and the PWM duty cycle parameter, determine the idling ratio parameter according to the ratio of the PWM duty cycle parameter to the speed parameter, and determine whether the functional motor enters an overload state according to the idling ratio parameter and / or changes in the idling ratio parameter.

47. The electric working vehicle according to claim 46, characterized in that: The speed parameter includes a motor speed parameter, and the idling ratio parameter represents a ratio of the PWM duty cycle parameter to the motor speed parameter; The overload identification unit determines whether the functional motor enters an overload state according to the idling ratio parameter and / or a change in the idling ratio parameter, including: During the operation of the functional motor, determining whether the idling ratio parameter is greater than or equal to a corresponding preset idling ratio parameter threshold; In response to the idle ratio parameter being greater than or equal to the corresponding preset idle ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

48. The electric working vehicle according to claim 46, characterized in that: The speed parameter includes a motor sector time parameter, and the idling ratio parameter represents a ratio of the PWM duty cycle parameter to the motor sector time parameter; The overload identification unit determines whether the functional motor enters an overload state according to the idling ratio parameter and / or a change in the idling ratio parameter, including: During the operation of the functional motor, determining whether the idling ratio parameter is less than or equal to a corresponding preset idling ratio parameter threshold; In response to the idle ratio parameter being less than or equal to the corresponding preset idle ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

49. The electric working vehicle according to claim 47 or 48, characterized in that: The idle ratio parameters include the idle ratio, the idle ratio difference and the idle ratio change rate; Wherein, the idling ratio refers to the ratio of the PWM duty cycle parameter to the speed parameter; The idling ratio difference refers to the difference between the idling ratios at two adjacent moments; The idling ratio change rate is used to characterize the change trend of the idling ratio at a corresponding moment; The overload identification unit determines whether the idle ratio parameter is greater than or equal to the corresponding preset idle ratio parameter threshold during the operation of the functional motor, including: At least one idle ratio parameter is obtained, and it is determined whether the at least one idle ratio parameter is greater than or equal to a corresponding preset idle ratio parameter threshold.

50. The electric working vehicle according to claim 12, characterized in that: The overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including: In response to the electrical parameter, the PWM duty cycle parameter and the first control strategy not matching, the overload identification unit is configured to select the electrical parameter and the PWM duty cycle parameter as the target operating parameter; The overload identification unit is also configured to monitor the electrical parameters and the PWM duty cycle parameters, determine the empty-to-electric ratio parameters based on the ratio of the PWM duty cycle parameters to the electrical parameters, and determine whether the functional motor enters an overload state based on the empty-to-electric ratio parameters and / or changes in the empty-to-electric ratio parameters.

51. The electric working vehicle according to claim 50, characterized in that: The overload identification unit determines whether the functional motor enters an overload state according to the air-to-electricity ratio parameter and / or the change of the air-to-electricity ratio parameter, including: During the operation of the functional motor, determining whether the air-to-electricity ratio parameter is greater than or equal to a corresponding preset air-to-electricity ratio parameter threshold; In response to the air-to-electricity ratio parameter being greater than or equal to the corresponding preset air-to-electricity ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

52. The electric working vehicle according to claim 51, characterized in that: The air-to-electricity ratio parameters include the air-to-electricity ratio, the air-to-electricity ratio difference and the air-to-electricity ratio change rate; Wherein, the air-to-electric ratio refers to the ratio of the PWM duty cycle parameter to the electrical parameter; The air-to-electricity ratio difference refers to the difference between the air-to-electricity ratio at two adjacent moments; The air-to-electricity ratio change rate is used to characterize the change trend of the air-to-electricity ratio at a corresponding moment; The overload identification unit determines whether the air-to-electricity ratio parameter is greater than or equal to the corresponding preset air-to-electricity ratio parameter threshold during the operation of the functional motor, including: Obtain at least one air-to-electricity ratio parameter, and determine whether the at least one air-to-electricity ratio parameter is greater than or equal to a corresponding preset air-to-electricity ratio parameter threshold.

53. The electric working vehicle according to claim 12, characterized in that: The overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including: In response to the power parameter, the PWM duty cycle parameter and the first control strategy not matching, the overload identification unit is configured to select the power parameter and the PWM duty cycle parameter as the target operating parameter; The overload identification unit is also configured to monitor the power parameter and the PWM duty cycle parameter, determine the idle power ratio parameter according to the ratio of the PWM duty cycle parameter to the power parameter, and determine whether the functional motor enters an overload state according to the idle power ratio parameter and / or changes in the idle power ratio parameter.

54. The electric working vehicle according to claim 53, characterized in that: The overload identification unit determines whether the functional motor enters an overload state according to the idle power ratio parameter and / or the change of the idle power ratio parameter, including: During the operation of the functional motor, determining whether the idle power ratio parameter is greater than or equal to a corresponding preset idle power ratio parameter threshold; In response to the idle power ratio parameter being greater than or equal to the corresponding preset idle power ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

55. The electric working vehicle according to claim 54, characterized in that: The empty work ratio parameters include empty work ratio, empty work ratio difference and empty work ratio change rate; Wherein, the idle power ratio refers to the ratio of the PWM duty cycle parameter to the power parameter; The air-work ratio difference refers to the difference between the air-work ratios at two adjacent moments; The air-power ratio change rate is used to characterize the change trend of the air-power ratio at a corresponding moment; The overload identification unit determines whether the idle power ratio parameter is greater than or equal to the corresponding preset idle power ratio parameter threshold during the operation of the functional motor, including: At least one empty power ratio parameter is obtained, and it is determined whether the at least one empty power ratio parameter is greater than or equal to a corresponding preset empty power ratio parameter threshold.

56. The electric working vehicle according to claim 12, characterized in that: The overload identification unit selects a target operating parameter from the multiple operating parameters for monitoring, and determines whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter, including: In response to the torque parameter, the PWM duty cycle parameter and the first control strategy not matching, the overload identification unit is configured to select the torque parameter and the PWM duty cycle parameter as the target operating parameter; The overload identification unit is also configured to monitor the torque parameter and the PWM duty cycle parameter, determine the air-torque ratio parameter according to the ratio of the PWM duty cycle parameter to the torque parameter, and determine whether the functional motor enters an overload state according to the change of the air-torque ratio parameter and / or the air-torque ratio parameter.

57. The electric working vehicle according to claim 56, characterized in that: The overload identification unit determines whether the functional motor enters an overload state according to the air-torque ratio parameter and / or the change of the air-torque ratio parameter, including: During the operation of the functional motor, determining whether the air-torque ratio parameter is greater than or equal to a corresponding preset air-torque ratio parameter threshold; In response to the air-torque ratio parameter being greater than or equal to the corresponding preset air-torque ratio parameter threshold, it is determined that the functional motor enters a heavy load state.

58. The electric working vehicle according to claim 57, characterized in that: The space-to-moment ratio parameters include space-to-moment ratio, space-to-moment ratio difference and space-to-moment ratio change rate; Wherein, the air-torque ratio refers to the ratio of the PWM duty cycle parameter to the torque parameter; The space-to-moment ratio difference refers to the difference between the space-to-moment ratio at two adjacent moments; The space-to-moment ratio change rate is used to characterize the change trend of the space-to-moment ratio at a corresponding moment; The overload identification unit determines whether the air-torque ratio parameter is greater than or equal to the corresponding preset air-torque ratio parameter threshold during the operation of the functional motor, including: At least one space-to-moment ratio parameter is obtained, and it is determined whether the at least one space-to-moment ratio parameter is greater than or equal to a corresponding preset space-to-moment ratio parameter threshold.

59. The electric working vehicle according to claim 12, characterized in that: In response to the second control strategy being the same as the first control strategy, the heavy load control unit controls and adjusts the functional motor based on the second control strategy, including: The overload control unit controls the operating parameter corresponding to the second control strategy to be reduced to a target value, and the target value is smaller than the value of the operating parameter corresponding to the second control strategy when the functional motor is in normal operation.

60. The electric working vehicle according to claim 12, characterized in that: In response to the second control strategy being different from the first control strategy, the heavy load control unit controls and adjusts the functional motor based on the second control strategy, including: The overload control unit controls the operating parameter corresponding to the second control strategy to be reduced to a target value, and the target value is less than or equal to an upper limit threshold of the operating parameter corresponding to the second control strategy when the functional motor is in normal operation.

61. An electric gardening vehicle, characterized in that: include: Frame; a functional mechanism, attached to the vehicle frame, comprising a functional motor and an output assembly driven by the functional motor to perform a specific functional operation; A controller component, used to control the operating state of the functional motor; The functional motor has a plurality of operating parameters, and the controller component has a plurality of control strategies corresponding to and matching the plurality of operating parameters for the functional motor; The controller assembly includes a heavy load identification unit and a heavy load control unit; The overload identification unit is configured to select a target operating parameter from the multiple operating parameters for monitoring, and determine whether the functional motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter; wherein the target operating parameter does not match a first control strategy currently adopted by the controller component for the functional motor; In response to determining that the functional motor enters the overload state, the overload control unit is configured to select a second control strategy from the multiple control strategies, and control and adjust the functional motor based on the second control strategy to make it exit the overload state.

62. An electric riding lawn mower, characterized in that: include: Frame; A carrying mechanism, arranged on the frame, for carrying a user; a mowing mechanism, attached to the frame, comprising a mowing motor and a cutter assembly driven by the mowing motor to perform a mowing operation; A controller component, used for controlling the operating state of the mowing motor; The mowing motor has a variety of operating parameters, and the controller component has a variety of control strategies corresponding to the various operating parameters for the mowing motor; The controller assembly includes a heavy load identification unit and a heavy load control unit; The overload identification unit is configured to select a target operating parameter from the multiple operating parameters for monitoring, and determine whether the mowing motor enters an overload state according to the target operating parameter and / or a change in the target operating parameter; wherein the target operating parameter does not match a first control strategy currently adopted by the controller component for the mowing motor; In response to determining that the functional motor enters the overload state, the overload control unit is configured to select a second control strategy from the multiple control strategies, and control and adjust the mowing motor based on the second control strategy to make it exit the overload state.

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